NAND and NOR gates are universal, which means that you can implement every possible Boolean function with them. Remember that the NOT gate can be implemented using either a NAND or a NOR. Implement the following functions using only NAND and NOT gates. Do not simplify the functions for this problem. a. (a + b) (c' +d) b. (a'b + b'c)' Implement the following functions using only NOR and NOT gates. c. (a + ab'c)' d. (((a + b)' + c) + d)