what is minimum number of NAND gates to implement XOR? i thought it in this way .first i found how many NAND gates are need to to implement XOR . if the two input it 'A' nd 'B' then XOR function =A'B+AB' so i need two NAND gates to invert A and B then for two AND gates i need another 4 NAND gates as each AND gate need 2 NAND gates . then for final OR gate i need another 3 NAND gate . so this will give the XOR function .To make it XNOR i need another NAND gate so total number of NAND gates=2+4+3+1=10 but in my MCQ question it has only a)3 b)4 c)5 d)6 i dont how to implement XNOR in one of above answers ,totally by NAND gates .can somebody help me ? Thanks !!!!!!!!!