If the Doctor Uses a Test That Indicates If a Man

If the doctor uses a test that indicates if a man is having nighttime erections, what is he likely checking for?

A) If the conditions should be classified as a primary or secondary problem.
B) If the condition is more likely to have a physiological cause vs. a psychological basis.
C) If the condition can be effectively treated with a drug like Viagra.
D) If the condition is situational or global.