Hi there!
Your correct answer will be 12.2 cm³.
This is how you get there:
1 mL = 1 cm³
With this one conversion factor, you can extrapolate the final answer. When you add the granite to the water, which is filled to 25.0 mL, the water level then moves to 37.2 mL. If you subtract the before volume from the volume after, you will get an answer of 12.2 mL. Then use the conversion factor and, voila! 12.2 cm³
I hope this helps!
Brady