Read the passage carefully and answer the following questions.
A dancer is demonstrating dance steps along a straight line. The position-time graph of the dancer is given here.
The average velocity of the dancer during time interval between t = 2 s to t = 9 s is
A 1 m s-1
B - 0.57 m s-1
C 2.75 m s-1
D - 0.29 m s-1