2. which of the following will change the equilibrium potential for na+?

1.the gating properties of the na+ channels

2.the concentration of the na+ on the inside of the cell versus the outside

3.the ion channels that are open in the cell

4.the resting membrane potential of the cell

Option C, the ion channels that are open in the cell

Explanation:

Ion channels work on the principle of identification of size of the pore.

The plasma membrane of neuron is slightly permeable to Na+ ion while it is highly permeable to K+ ion. The concentration of Na+ ion is higher outside the cell while it is lower inside the cell while the concentration of K+ ion is higher on the inner side of the cell as compared to the outer side of the cell. The ion gate is responsible for maintain this equilibrium. When sodium potassium pump works (or ion gate is considered open), it causes movement of ions against the gradient through active transportation.  

Hence, option C is correct

i believe your answer would be c.. : )