What Is the Significance of the 1940s Study by Keys

What is the significance of the 1940s study by Keys et al. in which healthy individuals placed on a semistarvation diet developed a preoccupation with food?

A) This study supports the idea that a preoccupation with food is a result of starvation.
B) This study demonstrates that a preoccupation with food is a natural event and not of medical concern.
C) This study shows that healthy individuals are likely to develop anorexia nervosa when placed on a semistarvation diet.
D) This study suggests that a preoccupation with food is a distinguishing characteristic between those with anorexia nervosa and those without it.