If graph of `y=f(x)` is symmetrical about the y-axis and that of `y=g(x)` is symmetrical about the origin and if `h(x)=f(x)dotg(x),t h e n(d^3h(x))/(dx^3)a tx=0` is (a)cannot be determined (b) `f(0)dotg(0)` (c)0 (d) none of these