Currently, the main cause of obsessive-compulsive disorder hasn't been known, but most cases of obsessive-compulsive disorder are accompanied by extreme phobia toward a certain things. (Such as germs)
People who have extreme phobia of germs can develop an irrational fears that their hands are at risk of germs contamination from touching the objects around them. This cause them to repetitively washing their hands within short period of time.
answer; /// (a) and (b) ; /// but i believe the correct answer is ; /apart from fines and jail time, driving under the influence puts the life of the driver and everyone else on the road at risk; (b)