+1. Word for word what I was going to post.This is possibly the worst reasoning ever. Both A and C are semiconductors.
I still think it's A. Even if the BoS says it's B, I still think it's A. I mean, what if we're trying to detect thermal radiation from a particularly cold person (he's been plowing the snow fields of siberia). Peak wavelength would be down and to the right ---> InSb semiconductor won't be as effective ---> HgCdTe is better for the job.