I've looked this question up and found it refers to a short story called "Flower Power".
Answer:
The option which best describes the act of stopping for flowers on the side of the highway for Mary is:
B. a ritual
Explanation:
A ritual can be defined as a fixed set of actions performed with certain regularity. It can refer to big as well as small, day-to-day actions. For instance, a Catholic mass is an example of ritual, but so is a person who gets up at the same time and immediately drinks some coffee every day.
In the story "Flower Power", Mary develops a small ritual. Every time she visits her grandmother at the hospital, she pulls over by the road and clips a bunch of wildflowers. She then puts the flowers inside a pitcher by her grandmother's bed. There is love and care behind those actions. The flowers are no longer just flowers, but a symbol for Mary's feelings and her relationship with her grandmother.