Sympathetic preganglionic axons enter a sympathetic chain ganglia. In order for these axons to reach collateral ganglia, they must now travel through:

Splanchnic nerves

Explanation:

Sympathetic preganglionic axons enter a sympathetic chain ganglia. In order for these axons to reach collateral ganglia, they must now travel through, splanchnic nerves.

a splanchnic nerve

Explanation:

The splanchnic nerve is a vasomotor nerve that is born in the lower thoracic ganglia of the sympathetic nerve and is distributed through the celiac and renal plexuses. This type of nerve is formed by preganglionic fibers from the spinal cord that pass through the paravertebral ganglia and then reach the celiac ganglia and plexus. The splanchnic nerve is of the utmost importance in the process that allows axons to reach the collateral ganglia, as axons must travel through the splanchcinic nerve.