5. [10 marks] You are to design a circuit, called a BCD checker, that takes a 4-bit number A3A2A Ao as input and determines whether it is a valid Binary Coded Decimal (BCD) code. It can be represented by the logic block: A, Ao The output BC Dout is 1 if the 4-bit input number is a valid BCD code and 0 otherwise. For example: If the input number is 0111 then the output would be 1 as 0111 is a valid BCD code. If the input number is 1100 then the output would be 0 as 1100 is not a valid BCD code. (a) [3 marks Construct the truth table for the output BC Dout of the BCD checker