Choose the set that consists of only prime numbers.

A
2, 4, 8, 12

B
13, 15, 17, 19

C
2, 5, 23, 29

D
3, 17, 29, 81

constant acceleration- a

constant velocity- c

no velocity or acceleration- b

explanation:

for body moving with a constant acceleration, the rate of change of displacement changes over time. this is proven by the increasing gradient of the curve (a) against time.

a body that is moving at constant velocity covers equal distances over equal periods of time, thus the straight line with a constant gradient c.

a stationary body   covers no displacement as time elapses. thus the flat line with   zero gradient.