Ali, a war veteran, has had nightmares, flashbacks, and anxiety attacks for the past three years. Ali is most likely suffering from _______________.

A) acute stress disorder
B) external locus of control
C) catastrophic stress
D) post-traumatic stress disorder (PTSD)

Ali's symptoms suggest that he is experiencing PTSD, which is a mental disorder that can develop after a person has experienced or witnessed a traumatic event, such as war. Symptoms include nightmares, flashbacks, and anxiety. Acute stress disorder (A) is a similar condition, but symptoms only last for a month after a traumatic event. External locus of control (B) is a personality trait that describes a person who believes their life is controlled by external factors rather than their own actions. Catastrophic stress (C) is a term used to describe stress caused by a major event, such as a natural disaster or terrorist attack. However, it is not a specific mental disorder.