Consider the parent function 

1. Note that 

2. When 
 function is increasing.
 function is increasing.
3. When 
 function is decreasing (see attached diagram for details).
 function is decreasing (see attached diagram for details).
The graph of the function 
 can be obtained by translating graph of the parent function h units to the left and k units up (h>0, k>0). This transformation does not affect the growth or decline of the function.
 can be obtained by translating graph of the parent function h units to the left and k units up (h>0, k>0). This transformation does not affect the growth or decline of the function.
In your case function is decreasing, then correct choice is D.