The answer is (b): the pendulum will rise exactly to a height of 30, assuming that no loss in energy occurs, as seen in an mpeg video by clicking your mouse on the photograph below.
This can be seen from conservation of energy: the initial gravitational potential energy with the pendulum bob held at the 30 level to the left of the photograph is converted into kinetic energy at the bottom of its path, then back to potential energy.With no loss it should again rise to 30.
