Option (C) is correct because according to the textbook context, short-circuiting occurs when the live wire and the neutral wire come into direct contact (due to damaged insulation or a fault in the appliance). In such a situation, the current in the circuit abruptly increases. The textbook explicitly states: 'In such a situation, the current in the circuit abruptly increases. This is called short-circuiting.' This heavy increase in current is why electric fuses are essential - they melt due to Joule heating and break the circuit to prevent damage to appliances and the circuit itself.