South Vietnam's President Diem (which is who I'm assuming you're talking about) was overthrown in a military coup. Following the overthrow of his government by South Vietnamese military forces, President Ngo Dinh Diem and his brother are captured and killed by a group of soldiers. The death of Diemcaused celebration among many people in South Vietnam, but also lead to political chaos in the nation.
A. Written is the definition of incredible. Hope this helps you out I know this for a fact only because I just had this same question a couple of days ago and got it correct with the answer A.
