AMC8 1999 Problem 3

Which triplet of numbers has a sum NOT equal to 1 ?

Answer Choices
A. \left(\dfrac{1}{2}, \dfrac{1}{3}, \dfrac{1}{6}\right)
B. (2,-2,1)
C. (0.1,0.3,0.6)
D. (1.1,-2.1,1.0)
E. \left(-\dfrac{3}{2},-\dfrac{5}{2}, 5\right)