When Brenda's Son Did Not Experience Any of the Claimed

Multiple Choice

When Brenda's son did not experience any of the claimed benefits from wearing a magnetic vest, she was told that magnets act differently on different body parts, that the vest might not have been properly secured, and that everyone's body reacts differently to magnet therapy. The therapist encouraged her to continue using the vest, saying that the healing effect would not be noticeable until her son had worn it longer. This example illustrates:

A) the use of "multiple outs."
B) descriptive research methods.
C) the practice effect.
D) the effect of demand characteristics.