The difficulty in this question is mainly the wording. The question stem itself tells you the mirror is 1 meter high. In order for the person to not see their whole reflection, you want them to be 1) taller than the mirror and/or 2) super close to the mirror. I believe the answer is D because the person is 4 meters tall and they are right next to the mirror. Imagine if you were 4 meters tall (13.1 feet) and the mirror only reached your ankles. Even if you look down at the mirror, you can't see your entire reflection. This is all based off qualitative thinking, so correct me if I'm wrong (didn't consult the book).
