Recently, there is ________ boom(繁荣)in population mobility and according to ________ national population survey of 2004, 17 percent of the population move every year．

1. A.
   the; a
2. B.
   a; the
3. C.
   /; a
4. D.
   the;/

Recently, there is ____ boom（繁荣）in population mobility and according to ____ national population survey of 2004, 17 percent of the population move every year.

A. the; a     B. a; the     C. /; a        D. the;/