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 of a cell differs from its emf by the drop across its internal resistance \( r \), and the sign of that drop depends on the direction of the current.

    \( \text{open circuit } (I = 0):\; V = E \)
    \( \text{cell supplying current}:\; V = E - Ir \lt E \)
    \( \text{cell being charged}:\; V = E + Ir \gt E \)

So, depending on how the cell is used, its terminal voltage can be equal to, less than or greater than its emf.