Refer to the Graph Showing World Record Times for Running

Refer to the graph showing world record times for running events of different durations.Each colored band in the graph (labeled 1-3) corresponds to the time courses of the three energy systems that supply fuel to the muscles. During which time period(s) are mitochondria the main source of ATP for the runner's muscles?

A) Time period 1, approximately 0-10 seconds
B) Time period 1, approximately 0-30 seconds
C) Time period 2, approximately 30-120 seconds
D) Time periods 2 and 3, approximately 30-10,000 seconds
E) Time period 3, approximately 120-10,000 seconds