I. The motion of the tyres of a moving car.
II. The motion of a loaded test tube oscillated
vertically.
III. The beating of the heart.
IV. A stone tied to a string and whirled round.
V. The motion of the pistons in a gasoline engine.
Which of the motions above is simple harmonic?

• A.III, IV and V only
• B.II, III and V only
• C.II, III and IV only
• D.I,II and III only
• E.