Concept: This question tests your understanding of the resting membrane potential of a neuron and what makes it 'excitable'.

Why (B) is correct: Neurons are excitable cells because their membranes maintain a polarized state at rest. This means there is an electrical potential difference across the membrane, with the inside being negatively charged relative to the outside. This resting potential is crucial for generating and transmitting nerve impulses when stimulated.

Why other options are wrong:

• (A) A depolarised state is when the membrane potential becomes less negative (or even positive), which is part of an action potential, not the resting excitable state.
• (C) A repolarised state is when the membrane potential returns to its resting negative state after depolarization, again, part of an action potential, not the inherent excitable state.
• (D) This is incorrect as option B is correct.

Common Mistake: Students often confuse the resting polarized state with the active depolarized state of a neuron.

NEET Tip / Mnemonic: Remember that a neuron is 'ready to fire' when it's Polarized (at Peace), maintaining a negative charge inside, waiting for a stimulus.

Correct Answer: (B)