From the combination of resistors with resistances values R_1= R_2= R_3=5 Ω and R_4=10 Ω, which of the following combination is the best circuit to…

From the combination of resistors with resistances values $\displaystyle \mathrm{R}_1=\mathrm{R}_2=\mathrm{R}_3=5 \Omega$ and $\displaystyle \mathrm{R}_4=10 \Omega$, which of the following combination is the best circuit to get an equivalent resistance of $\displaystyle 6 \Omega$ ?