Why not D?

Hi, D does not weaken the argument mostly because it does not give us enough information to undermine the idea that L reduces the risk of stroke. By telling us that people with high L eat more fruit than people with low L, one could add in there assumption that fruit and veggies reduce the risk of stroke. However, thats a big assumption, and we cannot add that in unless the argument tells us so. Additionally, perhaps the way that they do so (if they do) if via L.