A. -1.0 m/s
B. -0.50 m/s
C. -4.0 m/s
D. -2.0 m/s

C, -4.0 m/s

Explanation:

If the graph begins at a position of 14 at time zero, and approaches position 0 between time 3 and 4, then:

0-14/3.5-0 = -14/3.5 = -4

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.