Final answer:
When a conductor makes contact with a wire carrying current, a short circuit may occur, resulting in significant thermal power that can melt or burn the wire.
Step-by-step explanation:
When a conductor comes in contact with a wire carrying current to a load, a short circuit can occur. This is an undesired low-resistance path across a voltage source. If the insulation on wires becomes worn, two wires may come into contact creating a low resistance path. According to the formula P = V²/r, where P is power, V is voltage, and r is resistance, the power dissipated in the short is inversely proportional to the resistance. With very low resistance, the power can become extremely large, creating so much thermal power that the wire can melt or burn. Therefore, the correct answer is A) Short Circuit.