The terminal voltage of a cell

The correct answer is Option (4) → may be equal or less than or greater than its emf

The terminal voltage $V_t$ of a cell is related to its emf $\mathcal{E}$ and internal resistance $r$ by:

$V_t = \mathcal{E} - I r$, where $I$ is the current drawn from the cell.

Depending on the current and external conditions, $V_t$ may be equal to, less than, or slightly greater than the emf (in case of charging).

Answer: Terminal voltage may be equal, less than, or greater than its emf.