Which of the Following Sounds MOST Like Recreation as Your

Which of the following sounds MOST like recreation as your textbook defines it?

A) a student's time between getting out of class and going to work
B) a guitarist on tour who sells T-shirts and CDs at a merchandise table after each show
C) the "recess" period given to children in primary school when they can spend unstructured time on the playground
D) someone computing the amount and type of fuel needed to power a model rocket he or she wants to launch in a park