half-life

The decomposition of SOCl2 is first-order in SOCl2. If the half-life for the reaction is 4.1 hr, how long would it take for the concentration of SOCl2 to drop from 0.36 M to 0.045 M?
A.
0.52 hr
B.
1.4 hr
C.
12 hr
D.
33 hr
E.
> 40 hr