Answer
0.9
Work Step by Step
As we have seen examples of, we know that $\sin$ 120$^{\circ}$ = $\frac{\sqrt3}{2}$
Therefore: $sin$ 120$^{\circ}$ = 0.866
So, as the angle of $\sin$ gets larger, the result gets smaller. Therefore, $\sin$ 115$^{\circ}$ would be slightly more than $\sin$ 120$^{\circ}$.
0.9 is the option closest to 0.866