Once a preganglionic axon reaches a trunk ganglion, one of three things can happen to the axon. which of the following is not one of these three things?

1. the axon can ascend or descend the sympathetic trunk to synapse in another trunk ganglion.
2. the axon can course back into the spinal cord to synapse with preganglionic neurons in a different spinal segment.
3. the axon can synapse with a ganglionic neuron in the same trunk ganglion.
4. the axon can pass through the trunk ganglion and emerge from the sympathetic trunk without synapsing.