Which of the Following Is an Example of a Campaign

Which of the following is an example of a campaign activity taking place in "the parallel campaign?"

A) A member of Congress splits time between fund-raising and legislative activities.
B) A super PAC buys ad time criticizing a candidate for their views on abortion.
C) A candidate goes door-to-door to speak with voters directly.
D) Volunteers for a campaign make calls from a phone bank to take a push poll.