d
Here $R_2, R_3, R_4$ are in parallel
$\frac{1}{\mathrm{R}_{254}}=\frac{1}{\mathrm{R}_2}+\frac{1}{\mathrm{R}_5}+\frac{1}{\mathrm{R}_4}$
$\mathrm{R}_{254}=2 \Omega$
$R_{234}$ is in series with $R_1$ so
$\mathrm{R}_{\mathrm{eq}}=\mathrm{R}_{234}+\mathrm{R}_1=2+10=12 \Omega$
$\mathrm{i}=\frac{12}{12}=1 \mathrm{Amp}$