If $\alpha,\beta,\gamma\in (0,\large\frac{\pi}{2})$ then $\sin\alpha+\sin\beta+\sin\gamma$ is

Question

$\begin{array}{1 1}(a)\;> \sin(\alpha+\beta+\gamma)&(b)\;<\sin(\alpha+\beta+\gamma)\\(c)\;=\sin(\alpha+\beta+\gamma)&(d)\;\leq \sin(\alpha+\beta+\gamma)\end{array}$