See the electrical circuit shown in this figure. Which of the following equations is the correct equation for it?

• A

  ${\mathrm{\epsilon }}_1-\left({\mathrm{i}}_1+{\mathrm{i}}_2\right)\mathrm{R}-{\mathrm{i}}_1{\mathrm{r}}_1=0$

• B

  ${\mathrm{\epsilon }}_2-({\mathrm{i}}_1+{\mathrm{i}}_2\text{\hspace{0.17em})}\mathrm{R}-{\mathrm{\epsilon }}_1-{\mathrm{i}}_1{\mathrm{r}}_1=0$

• C

  $-{\mathrm{\epsilon }}_2-\left({\mathrm{i}}_1+{\mathrm{i}}_2\right)\mathrm{R}+{\mathrm{i}}_2{\mathrm{r}}_2=0$

• D

  ${\mathrm{\epsilon }}_1-\left({\mathrm{i}}_1+{\mathrm{i}}_2\right)\mathrm{R}+{\mathrm{i}}_1{\mathrm{r}}_1=0$