A particle moves in a circle of radius 5cm with constant speed, starting from the point (5cm,0) and moving anticlockwise. Its projection on the vertical diameter is noted. When the particle has rotated through an angle of 60∘, the displacement of the projection from the centre of the circle is
(a) 2.5cm
(b) −4.3cm
(c) 4.3cm
(d) 5.24cm