Answer:
the correct answer is C
Explanation:
This is a system with circular motion, there is a relationship between the linear and angular variables
     a = α r
with the cube going down the well, the tension of the leather is maintained therefore the acceleration of the cube is
     W = m a
     -mg = ma
     a = -g
this acceleration a is the same as that at the edge of the drum.
     α = a / r
where we can see that the angular acceleration is constant
consequently the correct answer is C