You Are a Forensic Biologist and Have Been Asked to Review

You are a forensic biologist and have been asked to review the files of an old, unsolved murder case. The autopsy report is missing a lot of important information, but you read that the victim had a thymus gland that was just starting to shrink. Based on this information alone, what can you conclude about the victim?

A) He was between 1 and 6 years old.
B) His lymphatic system was infected and being destroyed by an unknown virus.
C) He died of natural causes, most likely an autoimmune disease.
D) He was between 12 and 16 years old.