The correct option is A 0.75 V
In the question it is given that the current in the circuit is 0.25 A and the internal resistance is given as 3 ohms.
Hence, the potential difference across the resistance is given as V=IR = 0.25A×3Ω = 0.75V.
Hence, p.d. across the internal resistance of the cell is 0.75 V.