Renaldo Has No Specific Illness, Yet He Hasn't Felt Well

Renaldo has no specific illness, yet he hasn't felt well for several weeks, perhaps because he misses his parents since moving away to college. According to the definition of health supported by the World Health Organization:

A) Since laboratory tests do not reveal an illness, we may consider Renaldo healthy.
B) Renaldo is not in good health.
C) If Renaldo is not careful, he may become ill.
D) Renaldo's illness is probably all in his head.