Thanks for the question! The problem with (B) is that it uses language that is too extreme. Note that it says that “NO advertisers could offer promotions that give way computers free of charge.†In general, when the LSAT uses this kind of extreme language, you should be wary. It’s not always wrong, but it’s often the case that it makes the answer choice to extreme. Here, the stimulus doesn’t prove that there doesn’t exist somewhere a single advertiser that could offer a promotion that gave away computers free of charge under these circumstances. Perhaps, for example, by giving away free computers, more people would buy their other products. Since (B) is too strong, it’s not the right answer. Hope this helps! Feel free to ask any other questions that you might have.