How is muscle color related to muscle specialization?

Red muscles (extensor muscles) have large amount of myoglobin (protein transporting oxygen). Red muscles have slow and sustained contraction.
White muscles have less amount of myoglobin than red muscles and less mitochondria. White muscles have fast contraction. They perform fast work for short period of time, red perform sustained work for prolonged period.

Very hard to understand

The correct answer is "b"