Let f(x) = x2 and g(x) = sinx for all x∈R . then the set of all x satisfying (fogogof) (x) = (gogof) (x), where (fog) (x) = f(g(x)), is
a. ±√nπ,n∈{0,1,2,....}
b. ±√nπ,n∈{1,2,....}
c. π2+2nπ,nin{....,−2,−1,0,1,2....}
d. 2nπ,n∈{....,−2,−1,0,1,2,....}