Question: Penelope kicks the ball along the grass surface of a soccer field, then later she kicks it with the same force along an artificial turf field. The ball rolls for a longer time on the artificial turf than it does on the grass, which is due to the more smooth surface of the (A) artificial turf (B) grass.  Do not use A and B to answer the question but instead, choose between "artificial turf" and  "grass".
The answer to this question is:
artificial turf