Irrelevant. The argument addresses whether people were more likely to buy the product, not how many people bought the product. So it doesn’t matter when more people checked out.

This rules out the alternative hypothesis that most customers who bought an advertised product were already planning to buy it that day. This makes it more likely that the ad influenced their purchase.

This doesn’t help to establish that the advertisement itself caused people to buy the product. Also, (C) doesn’t say which consumers reported buying an advertised product every time they shop— maybe the consumers in (C) didn’t even hear the ad.

Irrelevant. Whether people remember hearing the ad doesn’t tell us whether they actually heard it. If they didn’t hear it, this would weaken the conclusion that the ad influenced their purchase.

Irrelevant. The fact that people only buy the product occasionally doesn’t explain whether the ad influenced their purchase on this occasion. They might have already planned to buy it that day.