In the Section "Investigating Life: Did a Myosin Gene Mutation

In the section "Investigating Life: Did a Myosin Gene Mutation Make Humans Brainier?",why did the researchers look for a human myosin gene containing a mutation in tissue samples from non-primates?

A) to determine if the myosin gene was being transcribed
B) to determine if the myosin gene was being translated
C) to determine if they had the myosin gene
D) to determine if they had the same deletion of two base pairs in the myosin gene
E) to determine if loss of the myosin gene made the non-human primates behave more like humans