A solid cylinder of mass $M$ and radius $R$ rests on a plank of mass $2M$ lying on a smooth horizontal surface. There is sufficient friction between the cylinder and the plank for pure rolling. If the plank is pulled with a horizontal force $F$, find the acceleration of the cylinder. A) $F / 2M$ B) $F / 5M$ C) $4F / 9M$ D) $F / 3M$