A uniform disc of mass M and radius R is mounted on an axle supported in frictionless bearings. A light cord is wrapped around the rim of the disc and a steady downward pull T is exerted on the cord. The tangential acceleration of a point on the rim is

• A

  $\frac{\mathrm{T}}{\mathrm{M}}$

• B

  $\frac{{\mathrm{MR}}^2}{\mathrm{T}}$

• C

  $\frac{2\mathrm{T}}{\mathrm{M}}$

• D

  $\frac{{\mathrm{MR}}^2}{2\mathrm{T}}$