The answer is (d): He cannot see more of himself in that size mirror, as seen in the three photographs below.
The three pictures were taken with OTTO 1m, 2m, and 3m from the mirror, respectively. We have adjusted the zoom on the camera so that only the edge of the mirror frame is visible, and the images of OTTO can be easily compared.
This is an easy problem to solve by ray tracing, which will be left to the inquisitive reader.
