Uniform convergent sequences of functions?

Calculus

Which of the following sequences of functions $\{f_n\}_{n=1}^{\infty}$ is/are uniformly convergent on its/their domain?

(A): $f_n(x) = \cos^{n}(x)$ on $\left[-\dfrac \pi2, \dfrac \pi2\right]$ .

(B): $f_n(x) = \dfrac{x}{n}$ on $\mathbb{R}$ .

(C): $f_n(x) = \dfrac{\sin(nx)}{n}$ on $\mathbb{R}$ .

Notation: $\mathbb R$ denotes the set of real numbers.