The Nurse Researcher Is Critiquing a Research Study That Involves

The nurse researcher is critiquing a research study that involves subjects undergoing chemotherapy for breast cancer.Which situation meets a criterion for inferring causality between performance of exercise and adaptation of the subjects receiving chemotherapy?

A) Adaptation behavior began before the exercise program was initiated.
B) Adaptive behavior occurred in the control group over time.
C) The level of adaptive behaviors increased proportionately with an increase in the intensity of the exercise.
D) No difference in adaptive behavior was observed between subjects in the experimental group and subjects in the control group.