Design a circuit (not Verilog) that can multiply a 4 bit number A by 1, 2, 3, or 4 to produce the result A, 2A, 3A, or 4A. You may use an n-bit adder as a generic block in your circuit (i.e. you do not need to design the adder circuit details). Hint: consider how shifting can be used to multiply by powers of 2