Why does the spinal cord have the right number of axons to innervate all the muscle cells? A. Each muscle cell sends a chemical message telling the spinal cord to make a neuron. B. The genes cause a...

Why does the spinal cord have the right number of axons to innervate all the muscle cells?
A. Each muscle cell sends a chemical message telling the spinal cord to make a neuron.
B. The genes cause a certain number of neurons to form and the same number of muscles to form.
C. Immature cells divide, with one daughter cell becoming a neuron and the other becoming a muscle.
D. The spinal cord makes an excess of neurons, but those that fail to innervate a muscle die.