Which of the Following Is a Factor Explaining Why Incumbent

Which of the following is a factor explaining why incumbent members of the U.S.House usually win reelection?

A) Voters perceive House races in terms of national issues,and polls show that voters believe that experience is important for those types of issues.
B) Congress as a whole is held in such high regard by the voters that individual members of Congress have a relatively easy time winning reelection.
C) Incumbents are much better known and funded than challengers are.
D) Incumbents often make enemies while in office.
E) Incumbents are perceived as all-powerful and unbeatable.