When Kate Exercises, She Either Swims or Runs

Multiple Choice

When Kate exercises, she either swims or runs. She wants to spend a minimum of 15 hours a week exercising, and she wants to swim 4 times the amount she runs. What is the minimum amount of time she must spend doing each exercise?

A) At least 3 hours running and 12 hours swimming.
B) At least 12 hours running and 3 hours swimming.
C) At least 1 hour running and 14 hours swimming.
D) At least 6 hours running and 12 hours swimming.
E) At least 6 hours running and 24 hours swimming.