Please answer the following question: Question: Maria decided to take her child to the park. She put her child in the stroller and went for a walk. Maria realized she was tired of pushing the stroller on grass after a much shorter distance than when she pushed the stroller on dirt. Maria then figured out that she could push the stroller for a longer distance on the dirt paths because there was (A) more friction (B) less friction.  Do not use A and B to answer the question but instead, choose between "grass" and  "dirt".
A:
dirt