A particle is constrained to move on a straight line path. It returns to the starting point after 10 sec. The total distance covered by the particle during this time is 30 m. Which of the following statements about the motion of the particle is false [CBSE PMT 2000; AFMC 2001]
(a) Displacement of the particle is zero
(b) Average speed of the particle is 3 m/s
(c) Displacement of the particle is 30 m
(d) Both (a) and (b)