On which of the following intervals is the function $f$ given by $f (x) = x^{100} + sin x –1$ strictly decreasing ?

Question

$(A)\; (0,1) \quad (B) \;\left( \large\frac{\pi}{2}, \pi\right) \quad (C)\; \left(0, \: \large\frac{\pi}{2}\right) \quad (D)\; \text{None of these}$