If Binding of a Small Molecule to a Regulatory Protein

If binding of a small molecule to a regulatory protein lowers the K_d of the protein/operator binding interaction, what can reasonably be stated?

A) The small molecule activates transcription by decreasing inhibition by the protein.
B) The small molecule inhibits transcription by increasing inhibition by the protein.
C) The small molecule activates transcription by increasing activation by the protein.
D) The small molecule inhibits transcription by decreasing activation by the protein.
E) None of these statements is reasonable.