Some biologists believe this is an ancient survival strategy, _______ a diet with 30 percent fewer calories than usual increased life span.

A. for which　　　 　　　B. to which　　 C. of which　　　 D. in which

Some biologists believe this is an ancient survival strategy, _______ a diet with 30 percent fewer calories than usual increased life span.

1. A.
   for which
2. B.
   to which
3. C.
   of which
4. D.
   in which

Some biologists believe this is an ancient survival strategy, _______ a diet with 30 percent

fewer calories than usual increased life span.

   A. for which       B. to which             C. of which       D. in which

 Some biologists believe this is an ancient survival strategy, _______ a diet with 30 percent

fewer calories than usual increased life span.

   A. for which       B. to which             C. of which       D. in which