Answer :
The correct answer is C. Social
Explanation:
The word Social refers to any related to the society or the collective life or interaction of people including the culture, conflicts, relationships and common aspects of the member that composed a society. This implies a social category is related to all the elements that concern the interaction of people in almost any context and including individuals with all type of features. Considering this, the personal relationships with friends at school are part of the social aspect or category as these relationships are related to the interaction of people in a certain context which in this case is the school and therefore concerns society. This means if your goal is to improve your personal relationships with your friends at school the category this goal falls into is the Social as it deals with the interaction between people which in this case is aimed at being improved.