a b c d

a

$\text{3 Resistors of } 2\Omega \text{ each are in series } R_S = 6\Omega$ $ 6\Omega \text{ is in parallel with } 2\Omega $ $\text{Equivalent resistance is } R = \frac{6\times 2}{6+2} \Omega = \frac{3}{2} \Omega$ $\Rightarrow I = \frac{3V}{3/2 \Omega} = 2 A$