Concept: This question tests the understanding of the properties of the axonal membrane during the resting potential, specifically its permeability to intracellular proteins.

Why (C) is correct: In the resting state, the axonal membrane is impermeable to the large, negatively charged protein molecules found within the axoplasm. These proteins contribute significantly to the negative charge inside the neuron at rest and cannot cross the membrane, helping to maintain the resting potential.

Why other options are wrong:

• (A) permeable: If the membrane were permeable, these proteins would diffuse out, altering the resting potential.
• (B) partially permeable: This implies some degree of permeability, which is not the case for these large proteins.
• (D) selectively permeable: While the membrane is selectively permeable to ions like Na${}^{+}$ and K${}^{+}$, it is not selectively permeable to these large intracellular proteins; it is impermeable.

Common Mistake: Students might confuse the general selective permeability of the membrane for ions with its specific impermeability to large intracellular molecules.

NEET Tip: Remember that the impermeability of the axonal membrane to large, negatively charged proteins inside the cell is crucial for maintaining the negative resting potential. These proteins are 'trapped' inside.

Correct Answer: (C)