well first i will tell you it is much easier to write in simple past for beginners in german not preterit. i know because ich wohne in deutschland. so try to us the GE form it works better for people learning german. unless your teacher wants preterit.
I think the answer is D) reflection of light rays
During the day or with any form of light source available, light reflects off of the human body all of the time so this explains why you are able to see yourself in a mirror. The light reflects off of you and off of the mirror allowing you to see yourself.
It's just called Forensic Psychology.
