Q. 18 Let, x1⊕x2⊕x3⊕x4 = 0 where x1, x2, x3, x4 are Boolean variables, and ⊕ is the XOR operator. Which one of the following must always be TRUE ?
(A) x1x2x3x4 = 0
(B) x1x3+x2 = 0
(C) x′1⊕x′3=x′2⊕x′4
(D) x1+x2+x3+x4 = 0
Answer: (C)
Explanation:
