Diem Is Pregnant with Identical Twins

Diem is pregnant with identical twins. She also suffers from schizophrenia. When her sons Wes and Cam are 19 years old, Wes is diagnosed with schizophrenia, but Cam is not. The twins are also different in personality: Wes is very impulsive, indulgent, and not very good at planning, while Cam is more reserved. When they have a conversation, Wes usually does all the talking and Cam the listening.
-What is a possible explanation for why only Wes was diagnosed with schizophrenia

A) Medical error. Since they are identical twins they should both be diagnosed with the disorder or not diagnosed with the disorder.
B) Wes experienced some type of traumatic brain injury and Cam did not.
C) Wes was closer to his mother and used her as a model in behavioural learning.
D) Wes experienced epigenetic changes that altered his phenotype.