A vertical string, suspended from a fixed point and having a small mass attached to the free end is set into oscillations. Which of the following statements about the system are correct? i. The potential energy of the mass is a minimum at the middle of the swing ii. Its kinetic energy is a maximum at the middle of the swing iii. The sum of the potential and kinetic energies is constant throughout the swing

• A.i,ii and iii
• B.i and ii only
• C.ii and iii only
• D.i and iii only