Choose the correct sequence for depolarization and repolarization.

(A) Stimulus applied at a site on polarized membrane.
(B) Increased permeability for ${\mathrm{Na}}^{+}$.
(C) Generation of action potential.
(D) Increase permeability for ${\mathrm{K}}^{+}$.
(E) Restoration of membrane potential.

Assertion ($\mathrm{A}$): In myelinated nerve fibres, action potentials are conducted at a faster rate.

Reason ($\mathrm{R}$): The myelin present between nodes of Ranvier has concentrated $\mathrm{Na}$ and $\mathrm{K}$ voltage-gated channels.

Identify $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ in the following graph regarding nerve impulse transmission.

Regarding  nerve impulse transmission following statements (A-D) are given. how many statement is/are incorrect ?

a. During resting state, axonal membrane is comparatively more permeable for ${\mathrm{K}}^{+}$ ions and nearly impermeable to ${\mathrm{N}\mathrm{a}}^{+}$ ions.

b. During resting state, ionic gradient across the membrane is maintained by active transport of ions by ${\mathrm{N}\mathrm{a}}^{+}-{\mathrm{K}}^{+}$ pump which transport $3{\mathrm{N}\mathrm{a}}^{+}$ into the cell and $2{\mathrm{K}}^{+}$ outside the cell.

c. During resting state, axoplasm inside the axon contains high concentration of ${\mathrm{K}}^{+}$ and negatively charged protein and low concentration of ${\mathrm{N}\mathrm{a}}^{+}$.

d. During resting state, axonal membrane is impermeable to negatively charged protein present in axoplasm.