3. El valor de $\sin\left(\dfrac{\pi}{14}\right) \sin\left(\dfrac{3\pi}{14}\right) \sin\left(\dfrac{5\pi}{14}\right) \sin\left(\dfrac{7\pi}{14}\right) \sin\left(\dfrac{9\pi}{14}\right) \sin\left(\dfrac{11\pi}{14}\right) \sin\left(\dfrac{13\pi}{14}\right)$ es:

(a) $1$      (b) $1/8$      (c) $1/32$      (d) $1/64$