PT 60 S3 Q2

A study found that consumers reaching supermarketcheckout lines within ... ...

Which one of the following, if true, most strengthens the argument?
(A) During the study, for most of the advertisements more people went through the checkout lines after they were aired than before they were aired.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Complete Section: LR-B, June '10 LSAT (PT 60 Sec. 3)