GMAT Reading Comprehension (RC) | Re: GMATPREP ChallengeQ -Historians have identified two dominant

Hello Experts:chetan2u ,Divyadisha ,mikemcgarry ,souvik101990 ,aditya8062 ,Nevernevergiveup ,carcass and others
Can someone please explain why Q1 - Answer1: a and NOT c?
1. The passage is primarily concerned with
A. identifying points of agreement between two groups
C. contrasting two approaches to solving a political problem

I selected C because (i think) contrasting encompasses both similarity and difference. Although focusing more on difference. Isn't that the case here? 1 para - differences