Describe how incumbency influences congressional elections

Simply because they've been elected before, incumbents have an edge. Generally, citizens liked them enough to vote for them previously, and, unless something drastic has happened, those positive feelings haven’t changed. To win in the first place, candidates had to pass muster with constituents. This is especially important during years when there isn’t a presidential election. During these elections, much of the voter turnout consists of party loyalists and activists.

It’s letter b because the area of the trapezoid is 72

I'm not sure but it could be c ( not a 100% sure )