The correct answer is A.
OBJ-3.2: While Edward was on vacation, the network file share’s permissions have likely been modified. Based on the fact that Edward’s account is connected to the domain and can send/receive emails, it cannot be his user account’s permissions causing the issue. The internet security options would also prevent him from sending/receiving mail, so that can be eliminated. Even if the operating system were updated, that would not affect the shared inboxes since they reside on the network file shares and not Edward’s computer.