Contents of posterior triangle of neck: (A) Occipital artery, spinal accessory nerve, hypoglossal, ascending pharyngeal artery, (B) Occipital artery, lesser occipital nerve, subclavian artery, spinal accessory nerve, (C) Occipital artery, spinal accessory nerve, subclavian artery, hypoglossal nerve, (D) Occipital artery, Lesser occipital nerve, ascending pharyngeal artery, vagus nerve
Answer is B. Contents of posterior triangle of neck :

Occipital artery.
Spinal accessory nerve.
Subclavian vessels.
Trunks of brachial plexus.
Great auricular nerve, lesser occipital nerve, supraclavicular nerve, transverse cutaneous nerve.
External jugular vein.