When Researchers Have Tested the Accuracy of Biorhythm Charts,which Are

When researchers have tested the accuracy of biorhythm charts,which are supposed to forecast daily fluctuations in mood,alertness,and physical performance based on a person's birthdate,they have found the charts

A) to be useful only for those working in outdoor occupations.
B) to be useful only for women and not for men.
C) to be useful only for healthy individuals with no chronic illnesses.
D) to be useless.