Laura is in class when she begins to feel uncomfortable, irritated and unable to focus on anything that is happening. She decides to leave class to get some fresh air. As soon as she tries to get out of her chair, she has an overwhelming attack of anxiety, her heart is beating very fast and she is having difficulty breathing. Laura is suffering from a(an) ______________ disorder.

A) panic
B) phobic
C) obsessive-compulsive
D) generalized anxiety