I think it could be either B. or D.
It could be B, because if they didn’t follow orders, they could have been facing severe punishment, including but not limited too beatings, torture, or even death. However they probably would need to say that after saying they were just following orders.
It could be D because if they were just following orders they were ignorant in the fact that they couldn’t come to the realization that what they were doing was plainly wrong and not simply following orders. They were participating in mass genocide and dozens of human rights violations.
