Once a sympathetic preganglionic axon reaches a trunk ganglion what can it do?

it can 1. synapse with a ganglionic neuron in the same trunk ganglion, 2. ascend or descend the sympathetic trunk to synapse in another trunk ganglion or 3. pass through the trunk ganglion and emerge from the sympathetic trunk without synapsing

The answer: Synapse with a parasympathetic neuron in the same trunk ganglion