A pendulum is deflected 90° from its vertical equilibrium position when released. Indicate the false statements.

I. The work of the force of gravity serves to increase the speed of the pendulum mass in its descent.
II. The work of the tension of the pendulum mass remains constant if air friction is not considered.
III. The mechanical energy of the pendulum mass remains constant if air friction is not considered.
a) Only II
b) Only I
c) Only III
d) I and II
e) I and III