Why Would Opponents of a Bill Prefer an Open Rule

Why would opponents of a bill prefer an open rule to a closed rule?

A) Members of the House can exercise their filibuster power and block the legislation.
B) The open rule allows the other chamber to make a decision on the bill first.
C) The open rule makes it easier to add amendments that may weaken its chances of passing.
D) An open rule means that a bill can be recalled even after it is passed.