People have lots of problems living in the central Australian desert, ____ the lack of water is the most serious one.

People have lots of problems living in the central Australian desert, ____ the lack of water is the most serious one.

　 A. of which　　　 B. which　　　 C. for which　　 D. where

People have lots of problems living in the central Australian desert, ____ the lack of water is the most serious one.

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

People have lots of problems living in the central Australian desert, ____ the lack of water is the most serious one.

   A. of which       B. which        C. for which      D. where  

People have lots of problems living in the central Australian desert, ____ the lack of water is the most serious one.

   A. of which       B. which        C. for which      D. where