A、I<sub>1sub>-I<sub>2sub>-I<sub>3sub>-I<sub>4sub> + I<sub>5sub>=0 B、I<sub>1sub>-I<sub>2sub> + I<sub>3sub>-I<sub>4sub>-I<sub>5sub>=0 C、I<sub>1sub>-I<sub>2sub>+ I<sub>3sub> + I<sub>4sub> +I<sub>5sub>=0 D、I<sub>1sub>-I<sub>2sub> + I<sub>3sub>-I<sub>4sub> + I<sub>5sub>=0