Solette is training for a triathlon, a race in which she must swim, bike, and run. Solette does not practice all three activities each day. Instead, she swims on days 1, 4, 7, and so on. She runs on days 1, 3, 5, and so on. She bikes on days 1, 6, 11, and so on. Solette swam, ran, and biked on Day 1. What will be the next day on which she does all 3 activities?
A. Day 7
B. 30
C. 31
D. 121