Either of them is. 1/(the other one). That's 'C' .
I don’t understand how I’m supposed to answer that if you have to watch a video and answer certain questions on certain pages which we don’t have
When the ruler is broughı near the inetal knob, it repels electrons in the metal. Electrons move away froni the ruler and down the metal rod. The knob now has a positive charge. The thin pieces of metal foil at the bottom of the metal rod now have a negative charge.
