Ok so please do not listen to the other person response. Fat does not turn into muscle. There is no process biologically that can do that. The answer is C. Running provides aerobic adaptations which means you are able to utilize oxygen more efficiently. In order for muscle to cope with this adoration it needs to recruit more slow twitch muscle fibres which are oxidative fibres. Thus by repetitive running of long distances for months will result in your muscles in the leg to covert from mixed fibres of fast and slow to predominantly slow twitch fibres that are capable of better utilizing oxygen. Thus, increasing muscular endurance which is the ability for muscle to not fatigue and last long during long bouts of exercise such as running. Further, if anything this individual would lose weight NOT gain weight due to burning fat. Also running is not anabolic and your muscle will not grow like it does after resistance exercise.
