Concept: This question tests the understanding of the properties of the neuronal membrane during its resting potential, specifically focusing on ion permeability and distribution.

Why (C) is correct: The resting axonal membrane is impermeable to the large, negatively charged proteins present in the axoplasm (fluid inside the axon). These proteins cannot cross the membrane and contribute significantly to the negative charge inside the cell at rest.

Why other options are wrong:

• (A) More permeable to Na⁺: The resting membrane is actually much more permeable to K⁺ ions than to Na⁺ ions.
• (B) Fluid inside the axon contains high concentration of Na⁺: The fluid outside the axon (extracellular fluid) has a high concentration of Na⁺, while the fluid inside (axoplasm) has a high concentration of K⁺.
• (D) Possesses a positive charge on the inner surface and negative charge on the outer surface: In the resting state, the inner surface of the membrane is negatively charged, and the outer surface is positively charged.

Common Mistake: Students often confuse the ion concentrations and membrane permeabilities during resting potential versus action potential.

NEET Tip: Remember the '3 Na⁺ out, 2 K⁺ in' rule for the Na⁺-K⁺ pump, which helps maintain the resting potential. Also, think 'K⁺ leak channels' for resting permeability.

Correct Answer: (C)