Imagine That a Group of Researchers Conducted a Single-Blind Study

Imagine that a group of researchers conducted a single-blind study designed to test the effectiveness of subliminal-message weight-loss tapes. Suppose the researchers found that everyone lost weight during the study, even those who were given tapes without any subliminal messages. This type of result would ​

A) indicate that the independent and dependent variables are negatively correlated.
B) provide evidence that subliminal tapes are effective in promoting weight loss. ​
C) be evidence of a placebo effect. ​
D) be evidence that the study contained confounding variables. ​