Parasympathetic preganglionic fibres travel in spinal nerves and:

1. The division has cranial and sacral origins. 2. Each uses its own kind of nerve. 3. Preganglionic fibers from the cranial region travel in cranial nerves, and sacral ones in spinal nerves. 4. So the answer is cranial nerves. _Source: OpenStax 'Anatomy and Physiology 2e', Ch 15 'The Autonomic Nervous System'_