Answer
The correct answer is:
(a) Both are to the right.
Work Step by Step
We think of the direction of the current as the direction that positive charges flow.
When Na+ ions move to the right, the current flows to the right, since the sodium ions are positive charges.
When Cl- ions move to the left, negative charge are flowing to the left. This is equivalent to positive charges flowing to the right, so the current also flows to the right in this case.
The correct answer is:
(a) Both are to the right.