The correct answer is D) A conference committee is formed to reconcile the different versions of the bill.
In order for a bill to become a law, both the House of Representatives and Senate must pass th exact same bill. When one part of Congress changes the bill, they must work with the other branch of Congress to pass the same version of the bill.
For example, if the House of Representatives passes one bill and the Senate takes that bill, revises it, and then passes a different version, that is when a conference committee is called. This committee works to find a compromise between the two different branches of Congress in order to create a bill that both the Senate and House of Representatives can agree on.