A Teenage Girl Had Recently Been Having Panic Attacks While

A teenage girl had recently been having panic attacks while shopping at the mall.She was sitting in her room feeling very depressed.To cheer her up, a friend suggested they both go to an exercise class.Shortly after the warm-up started, however, she had another panic attack.What is the best explanation for this occurrence?

A) She was angry with the friend for insisting that she go out.
B) The medication that had been prescribed for her was only treating the depression, not the anxiety.
C) The physical sensations experienced during exercise had become an internal cue for panic to occur.
D) The exercise class was an unconditioned stimulus that resulted in a panic attack.