In addition to gerrymandering,a major reason why so many members of Congress are elected
From safe districts is

A) local newspapers and television stations typically provide very favorable coverage to the incumbent party's candidates.
B) the natural geographic clustering of people who share a political ideology.
C) that once people move into a district that is very liberal or very conservative they tend to switch their ideology to match that of their new districts.
D) candidates for Congress usually change their partisan affiliation to match that of their districts.

The natural geographic clustering of people who share a political ideology is a major reason why many members of Congress are elected from safe districts. This means that certain areas or districts may lean heavily towards one political party or ideology, making it easier for candidates from that party to win elections in those areas. This is known as partisan gerrymandering. However, even in the absence of gerrymandering, safe districts can be created due to the natural clustering of like-minded people, making it difficult for candidates from other parties to win elections in those areas.