I see you wrote this 4 months ago so I might be late to have helped you but in case you're taking it in the future (and for anyone else struggling):

The way you realize that this is a strengthening question is by the question stem saying "if true" in reference to the answer choices. In other words, the question stem is asking you to take the answer choices as true and regard the stimulus as suspect. Strengthening questions are always questions that tell you the answer choices are all true (by saying something like "if true" when talking about the answer choices) and thus by default the stimulus is suspect.

Whereas MSS questions would say something like "if the stimulus/ if the above is true" or things like " the statements most strongly support what?" telling you that you should take the stimulus as true and the answers as suspect.

Lol I only got this one wrong because I read it as MBT instead of MBF LOL ughhhhh

Another way to look at it is by acknowledging that the argument already acknowledges that a marketing campaign is no gurantee of success. Meanwhile, the correct answer shows that, even if a marketing campaign IS a chance of "saving" the product, undergoing said marketing campaign for the new product will bring more overall harm than good.

Love picking E cause I didn't read "LEAST" helpful lol. I gotta make my eyes focus closely on every word.