Which of the following is correct for a gated D-type flip-flop?*The Q output is either SET or RESET as soon as the D input goes HIGH or LOWThe output complement follows the input when enabledOnly one of the inputs can be HIGH at a timeThe output toggles if one of the inputs is held HIGH

The correct answer is: "The output complement follows the input when enabled".

Here's why:

A D-type flip-flop, or data flip-flop, is a type of digital circuit that is widely used in computer systems for data storage. It has two inputs: D (data) and CLK (clock), and two outputs: Q and Q' (the complement of Q).

The operation of a D-type flip-flop is as follows:

• When the CLK input is HIGH, the value at the D input is transferred to the Q output. If D is HIGH, Q will be HIGH; if D is LOW, Q will be LOW. This is why we say that the output follows the input when enabled (the clock signal is what enables the flip-flop).

• The Q' output is always the opposite of Q. If Q is HIGH, Q' will be LOW, and vice versa.

The other options are incorrect:

• "The Q output is either SET or RESET as soon as the D input goes HIGH or LOW": This is not correct because the output Q only changes when the CLK input is HIGH, not as soon as the D input changes.

• "Only one of the inputs can be HIGH at a time": This is not correct because both inputs (D and CLK) can be HIGH at the same time.

• "The output toggles if one of the inputs is held HIGH": This is not correct because the output Q does not toggle (change from HIGH to LOW or from LOW to HIGH) if one of the inputs is held HIGH. The output Q only follows the D input when the CLK input is HIGH.