Generally, Senate Races Are More Competitive Than House of Representatives

Generally, Senate races are more competitive than House of Representatives races for all of the following reasons except

A) Senate incumbents face more experienced challengers.
B) Senate incumbents face better-financed challengers.
C) statewide constituencies are large enough that one party does not dominate them.
D) the two-year term of office for Senators does not allow them sufficient time to raise enough campaign money to discourage challengers.
E) Senate incumbents tend to ride the president's electoral "coattails" much more effectively than incumbents in the House of Representatives.