Concept: This question tests your understanding of the components and pathway of a reflex arc, a fundamental unit of the nervous system responsible for involuntary actions.

Why (b) is correct: The label (b) correctly points to the afferent neuron (sensory neuron) which transmits sensory impulses from the receptor towards the Central Nervous System (CNS). In a reflex arc, the sensory neuron carries the signal from the receptor to the spinal cord.

Why other options are wrong:

• (a) is incorrect because it points to the receptor, which initiates the impulse but is not the pathway itself.
• (c) is incorrect because it points to the efferent neuron (motor neuron), which carries impulses from the CNS to the effector.
• (d) is incorrect because it points to the effector (muscle/gland), which responds to the impulse but is not the pathway carrying the initial sensory signal.

Common Mistake: Students often confuse the afferent (sensory) and efferent (motor) pathways. Remember 'A' for Afferent (Arriving at CNS) and 'E' for Efferent (Exiting CNS).

NEET Tip / Mnemonic: A reflex arc typically follows the path: Receptor → Afferent Neuron → Interneuron (in CNS) → Efferent Neuron → Effector. Think of 'SAME DAVE' - Sensory Afferent, Motor Efferent; Dorsal Afferent, Ventral Efferent (referring to spinal cord roots).

Correct Answer: (B)