Answer: The light bulb will be off if the switch is open,
Explanation:
We know that the electric current cannot flow through an open circuit.
Therefore when the switch will be off, then the circuit is open and thus current cannot flow through it. Moreover each circuit has wires connected to each of the two terminals of the battery along with a light bulb.
Hence, the D is the correct option. " The light bulb will be off if the switch is open".