In the following figure `r_(1)` and `r_(2)` are `5cm` and `30cm` repectively. If the moment of inertia of wheel is `5100kg m^(2)` then its angular acceleration will be `:-`
A. `10^(-4)rad//s^(2)`
B. `10^(-3)rad//s^(2)`
C. `10^(-2)rad//s^(2)`
D. `10^(-1)rad//s^(2)`