A cyclist starts from the centre O of a circular park of radius two kilometre, reaches the edge P of the park, then cycles along the circumference and return to the centre along QO as shown in the figure. If the round trip takes 10 minutes, the net displacement and average speed of the cyclist (in metre and kilometre per hour) is

Options

A. `0, (pi+4)/2`
B. `(pi+4)/2,0`
C. `42.9, (pi+4)/2`
D. 0,42.9