What type of digital circuit can electronically divide the frequency of an AC signal?

The correct answer is a bistable multivibrator. This type of circuit is often implemented using flip-flops, which can switch states based on input triggers. By applying an AC signal to the input of a bistable multivibrator, it can toggle its output between two stable states, effectively dividing the frequency of the input signal. When configured properly, a bistable multivibrator can produce an output that reflects half the frequency of the input AC signal, functioning as a frequency divider.

The other options do not serve the same function. Astable multivibrators generate a continuous square wave output without any external triggering, making them unsuitable for frequency division tasks. Monostable multivibrators produce a single output pulse in response to each trigger event and do not maintain a state that can be used for frequency division. Inverter circuits merely flip the voltage state of a signal but do not provide the capability of dividing frequency. This highlights the bistable multivibrator's unique role in the realm of digital circuits for frequency division purposes.