(2) Among the following functions, the one that is both an odd function and monotonically increasing on the interval $(-\infty,+\infty)$ is ( ).
(A) $y=x^{2}+x$
(B) $y=x+2 \sin x$
(C) $y=x^{3}+x$
(D) $y=\tan x$
(2) C Hint: Verify one by one.