The Authors of Your Text Describe an Incident in Which

The authors of your text describe an incident in which a friend of theirs,Alan,found the body of an elderly neighbour.Despite obvious signs that she was murdered,Alan insisted that she died of old age.Why?

A) Only a very experienced police officer would have had the skills to determine if it were likely that a murder took place.
B) Alan found it too painful to believe she was murdered.
C) He was not particularly adept at social perception.
D) He was the real murderer, but wanted to cover up his crime.
E) His expectations that she died of old age led him to ignore evidence that she was murdered.