Answer:
Slow twitch.
Step-by-step explanation:
I don't know why my last answer was deleted, but here goes:
You would want slow twitch muscle fibers, as it is a slow, long distance race. For slow, efficient movement such as that needed for a marathon, slow twitch is best. (Best for long, aerobic exercises)
For fast, short, usually anaerobic exercises, powerful fast twitch muscles are better.
Intermediate twitch is the inbetween, best for short distance aerobic exercise.