Of the Following, Who Is Demonstrating a Compulsion

Of the following, who is demonstrating a compulsion?

A) Dan, who has a precise, daily coffee-making routine that cannot be disrupted
B) Connie, who has repeated doubts as to whether she turned the stove off before she left for work
C) Peter, who keeps picturing himself hitting his boss
D) Tom, who worries about the contamination on other people's hands and on door knobs