Final answer:
The external superior laryngeal nerve provides sensory innervation for the vocal cords and motor innervation for the laryngeal muscles, particularly the cricothyroid muscle.
Step-by-step explanation:
The external superior laryngeal nerve (SLN) provides both sensory and motor innervation to specific parts of the throat. Specifically, it has a sensory function for the mucosa above the vocal cords and a motor function to the cricothyroid muscle. Therefore, among the options provided, the correct answer is that the external superior laryngeal nerve's sensory innervation is for the vocal cords, and its motor innervation is for the laryngeal muscles, namely the cricothyroid muscle. Hence, the correct option is: b) Sensory: Vocal cords, Motor: Laryngeal muscles.