As the picture shows, he is a photographer.

As can be seen from the figure, the length of AB is 2cm, that is, 0.02m, and the exposure time is 1 1000s, so the average speed of AB segment is:

. v = XT = 0.02m 0.00 1s = 20m/s；

Due to the extremely short time, the instantaneous speed at the corresponding moment of point A is about 20m/s;

According to the relationship between the velocity and displacement of free falling body, v2=2gh, H = V22g = 2022× 10 = 20m.

So choose: C.