A cyclist slows down uniformly from 15m/s to rest in 5s. Which description best represents the velocity–time graph during this period?
a) Straight line slanting upward from 0m/s at t=0 to 15m/s at t=5s
b) Curve slanting downward, becoming flatter, starting at 15m/s and touching 0m/s at t=5s
c) Straight line slanting downward from 15m/s at t=0 to 0m/s at t=5s
d) Horizontal line at 15m/s throughout the 5s interval