Which of the following contribute to the overwhelming tendency of incumbents to win re - election in Congress?

A. Incumbents have greater name recognition which is important because many Americans do not pay very close attention to politics.
B. For US House seats, the drawing of district lines is often done by partisans in state legislatures, and they create "safe seats" for their party that are hard to overturn.
C. Incumbents typically have a lot more money to spend on their campaigns than the people who challenge them.
D. All of the above