What is the least possible value of (x y-1)^{2}+(x+y)^{2} for real numbers x and y ?
Answer Choices
A. 0
B. \dfrac{1}{4}
C. \dfrac{1}{2}
D. 1
E. 2
What is the least possible value of (x y-1)^{2}+(x+y)^{2} for real numbers x and y ?
Answer Choices
A. 0
B. \dfrac{1}{4}
C. \dfrac{1}{2}
D. 1
E. 2