66) If set x = {a, b, c, d}, then number of binary operations that can be defined on x is

67) The number of Boolean functions that can be deined for n Boolean variables over k-valued Boolean algebra are

68) The minimum number of NAND gates required to implement the Boolean function. A + AB' + AB'C is equal to

69) Which of the following logic expression is incorrect?

70) Even parity is being used for error checking computer data. If data word to be transmitted is 0101 0111, the value of the parity will be