Question ID:PT66 S4 Q12 Passage:Manager: Our company's mail-order sales have recently increased 25 percent. This increase started around the time we started offering unlimited free shipping, rather than just free shipping on orders over $50. Thus, our change in policy probably caused the increase. Stem:Which one of the following, if true, most strengthens the manager's argument? Correct Answer Choice:AChoice A:Mail-order sales have been decreasing for companies that do not offer unlimited free shipping. Choice B:The company did not widely advertise its change in policy. Choice C:The company's profits from mail-order sales have increased since the change in policy. Choice D:The company's change in policy occurred well after its competitors started offering unlimited free shipping. Choice E:Most companies offer free shipping only on mail-order purchases over $50.