What is the relationship between the motor neuron axons and muscle fibers?

    a.    Each axon innervates only one muscle fiber.
    *b.    The fewer muscle fibers a single axon innervates, the more precise the movements.
    c.    The more axons which innervate a single muscle fiber, the more precise the movements.
    d.    The more muscle fibers a single axon innervates, the more precise the movements.