a. 1100 meters.
b. Between B and C
c.1. Between point D and E
c2. Between point D and E
d. 3.7 m/s.
Explanation:
The girl travels the distance of 1100 meters from starting to the end. There is no motion occurs between B and C due to no change of distance value from 200 meters. Between point D and E, the girls covers 500 meters long distance and also covers fastest distance between point D and E because between point D and E, the girl covers 500 meters distance in 30 seconds which is the highest of all. The average speed of the girls is 3.7 meter/seconds if we divide total distance i.e. 1100 meters by time which is 300 seconds.