Answer: c (fundamental attribution error.)
Explanation:
Option A (mere exposure effect): this does not fit the expression of Ravi election loss, it is not stated that he was exposed to an event that made him lose his election ,or because of the exposure an event made him to send negative stories ,non of this example of mere exposure suites his actions
Option B( ingroup bias): not the concept that his opponent was in the same group has him.
Option C(
fundamental attribution error): this explains his action after his loss , his actions are results of frustration due to his loss .
Option D(frustration-aggression principle.), this principle is quite the same ,but aggression doesn't make it the right answer, their is no form of aggression from His actions such as spreading false rumors.
In conclusion, option c is the best answer as he acted out of frustration.