Richard Is Participating in a Research Study Involving a New

Richard is participating in a research study involving a new pain medication.But he is not actually receiving the biologically active medication.Research suggests that he:

A) is most likely to fall into the group of participants that sometimes respond to placebo.
B) is likely to always respond to placebo.
C) will not respond at all to the placebo.
D) he is more likely to respond to placebo because he is male.