Which of the following are solutions to the equation sinx cosx = 1/4? check all that apply.
a. π/3+nπ/2
b. π/12+nπ
c. π/6+nπ/2
d. 5π/12+nπ

The solution is B. π/12+nπ

proof 
sinx cosx = 1/4 is equivalent to  2 sinx cosx = 1/2 or sin2x =1/2
so 2x = arcsin(1/2) = π/6 + 2nπ,  so x = π/12+nπ