During resting state of neuron, axonal membrane is 

A. More permeable to ${\mathrm{K}}^{+}$.
B. Nearly Impermeable to ${\mathrm{N}\mathrm{a}}^{+}$.
C. Impermeable to negatively charged proteins present in the axoplasm.

- The high concentration of ${\mathrm{K}}^{+}$ and negatively charged proteins and low concentration of ${\mathrm{N}\mathrm{a}}^{+}$ in axoplasm.

- In contrast, the fluid outside the axon contains a low concentration of ${\mathrm{K}}^{+}$, a high concentration of ${\mathrm{N}\mathrm{a}}^{+}$ and thus form a concentration gradient.

- These ionic gradients across the resting membrane are maintained by the Na–K pump which actively transports $3{\mathrm{N}\mathrm{a}}^{+}$ outwards for $2{\mathrm{K}}^{+}$ into the cell.

- The outer surface of the axonal membrane is positively charged. The inner surface of axonal membrane is negatively charged.

- The axonal membrane is polarised and the potential difference is known as resting potential.