This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Facial Nerve And Its Disorders, Subject name: ENT
Frey's syndrome is due to: 
Select and explain. 
A. Aberrant cross-innervation of post-ganglionic parasympathetic fibres for parotid to postganglionic sympathetic fibres supplying the sweat glands of skin, B. Pre-ganglionic parasympathetic fibres of parotid to post-ganglionic sympathetic fibres of sweat glands of skin, C. Post-ganglionic parasympathetic fibres secretomotor of the parotid to pre-ganglionic sympathetic fibres of sweat glands of skin, D. None of the above
A: Aberrant cross-innervation of post-ganglionic parasympathetic fibres for parotid to postganglionic sympathetic fibres supplying the sweat glands of skin
Answer: A: Aberrant cross-innervation of post-ganglionic parasympathetic fibres for parotid to postganglionic sympathetic fibres supplying the sweat glands of skin 
Explanation: Both fibres are post-ganglionic.Secretomotor fibres to parotid originate in tympanic branch of CN IX, travel through middle ear, relay in otic ganglion and supply the parotid through auriculotemporal. Similarly, secretomotor fibres to sweat glands of the skin over the parotid area are sympathetic in nature and are post-ganglionic as they relay in cervical sympathetic ganglia.Aberrant re-innervation, i.e. secretomotor fibres of parotid now making connections with secretomotor fibres of sweat glands causes Frey's syndrome or gustatory sweating. Sweating occurs over the preauricular skin in response to stimulus to secrete saliva from the parotid.