jmc

Clearly the arrow marks a value between $10.25$ and $10.5$, so only $\text{C}$ and $\text{D}$ are possible. Looking, we see that the arrow is closer to $10.3$, so $\boxed{\text{D}}$ Each part of the semicircle is one fourth of it, so we see that the answer is between $10.25$ and $10.5$. THe arrow is pointing a little in front of The middle of $10.25$ and $10.5$.Therefore, we have that $\boxed{10.3}$ is our answer --- stjwyl