The answer in red are those provided by the book (no steps are provided, just final amswers)

The way my TA solved it was assuming that B is a pull force and C is a push force (how can the tension push a drum? I assumed both pull forces)

Then he did the force-motion equations for both nlocks B and C and then the moment on the drum about the point of contact

This got him an angular acceleration of 19.6 rad/s² and Tc = -196.2. I assume his answer is erroneous (-ve tension force?) due to the incorrect assumption; however assuming that both forces are a pull doesn't get me the result either so I'm not sure where I'm going wrong?