Two pulleys (shown in figure) are made of the same metal with density \rho. Pulley A is a uniform disk with radius R. Pulley B is identical except a circle of R / 2 is removed from the center. When two boxes M=\alpha m(\alpha>1) are connected over the pulleys through a massless rope and move without slipping, what is the ratio between the accelerations in system \mathrm{A} and \mathrm{B} ? The mass of pulley \mathrm{A} is M+m.
Answer Choices
A. a_{A} / a_{B}=47 / 48
B. a_{A} / a_{B}=31 / 32
C. a_{A} / a_{B}=15 / 16
D. a_{A} / a_{B}=9 / 16
E. a_{A} / a_{B}=3 / 4
