Which Voting Behavior by a Representative Indicates Delegate Behavior

Which voting behavior by a representative indicates delegate behavior?

A) Voting with the representative's party on an issue
B) Voting with the president on a bill if the president promises to campaign for that representative at reelection time
C) Voting the way the representative thinks best, even if the vote is against the wishes of a large number of constituents, because the representative knows that no matter which way the vote is cast, a large number of constituents will be offended
D) Trading votes on an issue of low importance with another House member to gain a voting favor on another bill
E) Voting according to the results of a telephone survey regarding the preference of district constituents