Final answer:
PTSD is now the leading mental disorder among soldiers returning from Afghanistan or Iraq.
Step-by-step explanation:
The correct answer is a) PTSD, which stands for Post-Traumatic Stress Disorder. PTSD is now the leading mental disorder among soldiers returning from Afghanistan or Iraq. It is an anxiety disorder that occurs after experiencing severe psychological trauma. Soldiers who have been exposed to combat situations may develop symptoms such as intrusive memories, flashbacks, nightmares, and hypervigilance.