Which Statement Summarizes the Main Function of a House Whip

Which statement summarizes the main function of a House whip?

A) to serve as an administrative assistant to the Speaker of the House and the majority leader
B) to count the votes on a piece of legislation and convince other party members to vote a certain way
C) to energize the voters leading up to an election to convince them to vote for a certain candidate
D) to shape the party's overall platform and legislative agenda and present it to the Speaker