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

In the section "Investigating Life: Did a Myosin Gene Mutation Make Humans Brainier?",how can the deletion of the two base pairs in the myosin gene only affect the temporalis muscle?

A) The gene was transcribed only in the temporalis muscle.
B) The deletion was present only in DNA in the temporalis muscle.
C) Other muscles also transcribe the myosin gene.
D) The temporalis muscle also transcribes other myosin genes.
E) Other muscles can repair the deletion.