Which Describes the Action of a Ligand's Competitive Antagonist

Multiple Choice

Which describes the action of a ligand's competitive antagonist?

A) It decreases the amount of ligand required to activate the protein.
B) It blocks the binding of the ligand to its binding site and prevents activation of the protein.
C) It binds to a different binding site on the protein,altering the protein shape so that a ligand cannot bind.
D) When present,it increases the binding of a ligand to its receptor.