Let f(x) = x|sin x|, x ∈ R. Then
(A) f is differentiable for all x, except at x = nπ, n = 1, 2, 3,….
(B) f is differentiable for all x, except at x = nπ, n = ±1, ±2, ±3,….
(C) f is differentiable for all x, except at x = nπ, n = 0, 1, 2, 3,….
(D) f is differentiable for all x, except at x = nπ, n = 0, ±1, ±2, ±3,…