Solution

The correct answer is 2) A, C Only.

Key Points

• Sequential circuits are types of circuits where the output depends not just on the current inputs, but also on the history of inputs. This means they have memory elements that store previous states.
• Flip flop is a basic memory element used in sequential circuits, which can store one bit of data.
• Counter is a sequential circuit that goes through a prescribed sequence of states upon the application of input pulses.

Additional Information

• Multiplexer (MUX) is a combinational circuit that selects one of many input signals and forwards the selected input into a single line. It does not store any state information, hence it is not a sequential circuit.
• Decoder is also a combinational circuit that converts binary information from n input lines to a maximum of 2^n unique output lines. It does not have memory, so it is not a sequential circuit.
• Adder is a combinational circuit used for adding binary numbers. It does not store any state information, hence it is not a sequential circuit.