Which of the following has no solution?
A{x | x ≤ 1} and {x | x ≥ 1}
B{x | x < 1} and {x | x > 1}
C{x | x ≤ 1} or {x | x ≥ 1}
A{x | x ≤ 1} and {x | x ≥ 1}
B{x | x < 1} and {x | x > 1}
C{x | x ≤ 1} or {x | x ≥ 1}