The potential difference between points A and B is:

$\frac{10}{3}$ V

The correct answer is Option (2) → $\frac{10}{3}V$

The net resistance of the circuit ($R_{net}$),

$\frac{1}{R_{net}}=\frac{1}{2+4}+\frac{1}{2+1}$

$\frac{1}{R_{net}}=\frac{1}{6}+\frac{1}{3}=\frac{3}{6}$

$⇒R_{net}=2Ω$

$I=\frac{V}{R}=\frac{10}{2}=5A$ [Using Ohm's law]

Current going through (2, 1) = $\frac{10}{3}A$

Current going through (2, 4) = $\frac{5}{3}A$

$V_A=10-2×\frac{5}{3}=\frac{20}{3}V$

$V_B=10-\frac{20}{3}=\frac{10}{3}V$

$∴ V_A-V_B=\frac{20}{3}-\frac{10}{3}=\frac{10}{3}V$