The value of $\sin\large\frac{\pi}{18}$$+\sin \large\frac{\pi}{9}$$+\sin \large\frac{2\pi}{9}$$+\sin \large\frac{5\pi}{18}$ is given by

Question

$\begin{array}{1 1}(A)\;\sin\large\frac{7\pi}{18}+\normalsize \sin \large\frac{4\pi}{9}&(B)\;1\\(C)\;\cos \large\frac{\pi}{6}+\normalsize \cos \large\frac{3\pi}{7}&(D)\;\cos \large\frac{\pi}{9}+\normalsize \sin \large\frac{\pi}{9}\end{array}$