"Feel out of sorts", as it is used in the second paragraph could best be replaced by _________.

A．moods can have an influence on people's emotions
B．aerobic exercise can help people better use oxygen
C．swimming, walking, or running is an efficient cure for a bad mood.
D．scientists have provided people with many tranquilizers

A．A procedure is explained and its significance is emphasized.
B．A problem is examined and solutions are given.
C．Two contrasting views of a problem are presented.
D．Recent pharmacological advancements are outlined in order of importance.