Chassaignac's tubercle is:

Ans. C. Carotid tubercle of C6 vertebraeThe anterior tubercle of the sixth cervical vertebra is known as the carotid tubercle or Chassaignac's tubercle. This separates the carotid artery from the vertebral artery and the carotid artery can be massaged against this tubercle to relieve the symptoms of supraventricular tachycardia. The carotid tubercle is also used as a landmark for anesthesia of the brachial plexus and cervical plexus.