Help please and thank you!

Answer:
Option A
Explanation:
[tex]\rightarrow \sf sin\left(\dfrac{7\pi }{6}\right)[/tex]
[tex]\rightarrow \sf \sin \left(\pi +\dfrac{\pi }{6}\right)[/tex]
[tex]\rightarrow \sin \left(\pi \right)\cos \left(\dfrac{\pi }{6}\right)+\cos \left(\pi \right)\sin \left(\dfrac{\pi }{6}\right)[/tex]
[tex]\rightarrow \sf 0 * \dfrac{\sqrt{3}}{2}+\left(-1\right) * \dfrac{1}{2}[/tex]
[tex]\rightarrow \sf -\dfrac{1}{2}[/tex]