Just a couple of quick thoughts, since Mike is already on this one. So, we’ve got two groups; one group stretches, and other doesn’t. If (D) is true (remember, on a weaken question, you can assume that each answer choice is true for the sake of analysis), then the stretching group (let’s call them Group A) is going to be more injury prone than the non-stretching group (let’s call them group B). But what happens? Group A, *despite the fact that they’re more injury prone than Group B*, gets the same number of injuries. That’s a surprising result, and the only difference between the groups that we know of to explain it is that they stretched.