In a Comprehensive Headache Treatment Program, People Who Were Low

In a comprehensive headache treatment program, people who were low users of analgesic medications

A) improved less than people who were using medication only.
B) improved more than people who were using medication only.
C) showed no improvement.
D) showed improvement; however, it was later found that many people in the study were taking analgesic medications outside the confines of the study causing the results of the study to be skewed.