A lift is moving up at constant speed. Consider the following statements.

I. The tension in the string is constant. 

II. The K.E of the elevator is constant.

III. The gravitational P.E of the earth lift system is constant. 

IV. The acceleration of the elevator is zero. 

V. The mechanical energy of the earth lift system is constant. 

Choose the correct option.

A

Only II and V are true

B

Only IV and V are true

C

Only I, II and III are true

D

Only I, II and IV are true