Too much socializing in the workplace can
a. keep you from joining a clique.
b. you become a supervisor.
c. keep you from reaching your performance goals.
d. add balance to your horizontal relationships.

Too much socializing in the workplace can C. keep you from reaching your performance goals. The questions clearly says 'too much,' which implies something negative, which means that B and D are not correct. A could be correct, but that's not really an important option, which is why I'd say it is incorrect. C is correct - if you socialize with people too much, spend time with them, have fun, you won't have the time to focus on your job and thus your performance will deteriorate.