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 prevents a bill's supporter from making further demands on minority party legislators.
D) The open rule makes it easier to add amendments that may weaken the bill's chances of passing.