Answer:
c) concern of contracting syphilis from a handshake
Explanation:
An Obsession can be rightly defined as those recurring thoughts, ideas, urges, images or feelings which one experiences as intrusive and unwanted, It causes distress and anxiety for most people for most people.
Obsession causes people to have compulsion, these are repetitive behaviours or some kind of mental acts which one compels himself to do to counter an obsession.
An example of obsession is one having concern of contracting syphilis from a handshake.
And an example of compulsion is constant hand washing.