What occurs when there is an open circuit?

An open circuit is a condition where the path for electric current is broken, preventing it from flowing. In this scenario, the circuit is incomplete due to a disconnection or a broken component, which means that there is no way for the electrons to travel through the circuit. Therefore, the current flow is halted entirely. This is why the correct answer is that there is no current flow in an open circuit.

Understanding this concept also highlights why the other options do not apply. Excessive current occurs in short circuits or faulty conditions where resistance is drastically reduced, while normal current flow might be expected in a properly functioning closed circuit. Fluctuating current typically occurs due to varying loads or supply and is not relevant in the context of an open circuit where current is absent entirely.