This is actually an incorrect summary of why A is wrong and this type of answer choice will come around again, so please don't think this summary is correct. As JY mentions, this AC was actually used on this test but for another question. It isn't wrong because it assumes that sales would have been equal or higher than sales under the adoption of the campaign.

This answer choice is incorrect because it assumes the "competitor's advertisement campaign" was used which we actually don't know if the competitor had a campaign or if any campaign was ever used (I think this second assumption actually can be made but JY thinks differently). The Marketing Consultant's argument is that sales were bad and then assumes it is because of an ill-conceived campaign.

(A) is a decent answer if we remove the "competitor's advertisement campaign" (and of course as JY mentions assume there was a campaign) because the marketing consultant is failing to show that the campaign was actually the cause of the demise of the product and incorrectly assumes that without the campaign sales would have been better. The campaign could have been great but the product could have sucked or some other unrelated economic issue caused the product to fail.

Which is what (B) is saying without the assumptions of (A). (B) is saying there is this other reason for the product to fail that wasn't the campaign.

Assumption: The build-up of creosote makes WBS more dangerous than OFP.

Loophole: What if OFPs have another variable that makes them more dangerous than the WBS?

A - Talking about a select few WBS, still, the majority are more dangerous if the assumption is correct.

B - Doesn't make WBS any less dangerous, if the assumption is correct than WBS is still more dangerous if used equally as often.

C - Perfect! Here is a separate variable that tells us the FP is more dangerous and makes the assumption incorrect.

D - WBS produces more and thus more dangerous if the assumption is correct.

E - Cool, us in cold climates still have to use them and if the assumption is correct than WBS is still more dangerous.

Tough question, no doubt. I think the biggest issue is we are looking for an answer that does the best job of weakening the hypothesis. I think this problem suffers from not having a truly great AC that 100% weakens the hypothesis. Here is a brief write up in case you need a little more help.

Assumption: The large amount of ferrous material would cause an increase in algae enough to lower CO2 in the air bubble.

Loophole: What if the ferrous material didn't have enough effect on algae to change the levels of CO2?

A - Diatoms haven't changed since the ice age. Irrelevant information. This doesn't hurt or help our assumption about ferrous material leading to Algae growth.

B - Diatoms today would be increased by ferrous material. This strengthens the argument. Supports the hypothesis in saying ferrous material can lead to algae growth.

C - Air bubbles contain another material. Okay, so there is not much to go off of here. There is just way too many assumptions here for this answer to be the best choice. What if the other material has no effect on the CO2. Then this answer choice is completely irrelevant. Although there could be a magic material that can help destroy our assumption, we just don't know since there isn't enough information given.

D - Shells from dead diatoms didn’t increase on the sediment floor NEAR Antarctica. This is essentially saying there was no increase in this form of algae caused by the ferrous material. Great, what about other forms of algae? Diatoms are simply one form of algae. This does weaken our hypothesis to a small extent though.

E - Large increase in ferrous material doesn't harm the Algae This again, although not as well, supports the hypothesis. If there was a massive increase in ferrous material then there would be no harm to algae at the very least.

Obviously, it's not perfect, but A B D are instantly thrown-out and you're left with C & D. C is super vague but potentially could hurt our hypothesis and D provides a specific example that does, although on a small scale, hurt our hypothesis. We have to remember that every correct AC can be reflected in the passage. C doesn't have enough information to help, so D is the better choice.

Specifically to answer your questions:

1) sediment near Antarctica didn’t seem relevant. - You're not wrong. If you just remove the sediment from the AC, "The ocean floor near Antarctica shows no increase in diatom shells during the last ice age", we still have enough for this to weaken the hypothesis.

2) what their shells had to do with anything about promoting growth - Nothing about growth, but the shells indicate that there wasn't an increase in diatoms during the last ice age. Meaning the ferrous didn't increase this form of algae.

If I re-write D in my own words and say: shells from dead diatoms (which like I guess I’m supposed to assume is right???) didn’t increase on the sediment floor NEAR Antarctica. The AC actually states "shells that diatoms leave when they die", you don't have to assume this since it's given.

I hope it helps. I personally try to write out the assumption during BR to make going through each AC easier.

@ebbyaldaoud858 said:

@kestes2785 said:

@ebbyaldaoud858 said:

4/5 avg isn’t bad at all . Review it later but don’t get hung up about it.

In general, lets say on the strengthening questions I'm struggling a bit more maybe only averaging 50% correct. Should I stop an review the section?

Rule of thumb is focusing on your weaknesses. Once those are covered you move onto perfecting the other sections which you did better in. Review the cc lesson on strengthening and the idea of support. If you’re just starting off go slow, and take your time. One mistake I did was rush through the cc. I ended up having to review it again. Once you learn a concept try to drill it .

Awesome! Thank you for the advice.

@ebbyaldaoud858 said:

4/5 avg isn’t bad at all . Review it later but don’t get hung up about it.

In general, lets say on the strengthening questions I'm struggling a bit more maybe only averaging 50% correct. Should I stop an review the section?