Answer:
A. prevent the Senate from voting on a bill
Step-by-step explanation:
The filibuster is a political tactic or procedure employed by members of the Congress, especially by Senators, in which one or more members intentionally give long and often irrelevant speeches to debate a proposed piece of legislation, in order to delay or prevent the chamber from voting on a bill. However, when this happens, a senator may invoke cloture, which it's their only defense to bring the debate to a quick end.