Answer: c)lithium carbonate
Step-by-step explanation:
Lithium Carbonate is the drug used for reduction of aggressiveness ,stabilization of mood, curing depression, reducing mania frequency ,severeness of mind etc in a person.
According to the question,Cecile should take lithium carbonate for making herself feel better from depression, isolating behavior,hopeless feeling etc .
Other options are incorrect because tranquilizer,anti-psychotic or an antidepressant is not the drug to make Cecile's situation better.Thus, the correct option is option(c).