Final answer:
Running 10 miles three times a week would result in an increase in muscular endurance.
Step-by-step explanation:
The correct answer is C. Increase in muscular endurance.
When an individual starts running 10 miles three times a week, it primarily targets the cardiovascular system and builds endurance in the leg muscles.
This activity will increase muscular endurance as the individual's leg muscles adapt to the demands of running longer distances and become more efficient at sustaining the activity for a longer duration.
Learn more about Effects of running on muscular endurance