Help please, 30 pts (I'm stuck between C and D) What is interleaving?

A. It’s when you try to think about too many things at once and you can’t remember any of them.

B. It’s when you pace back and forth while you study.

C. It’s when you study the same different subjects at the same time.

D. It’s when you study different ideas within the same subject.

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.