Read the section "Sweat Works, But Fake Sweat Works Better." Which sentence from the section explains WHY real sweat made less power than man-made sweat? A If the electrodes are connected to a device, the electricity can power it. B The device made enough power to light LEDs. C That may be because there hadn't been enough sweat on the runners' shirts. D They might be helped by working with other systems that use sweat, says Seokheun Choi.