Which set of ordered pairs represents y as a function of x?
A. {(4, square root of 17), (2, square root of 6), (1, square root of 3), (1, square root of 10)}
B. {(-7, 2.9), (-15, 5.9), (-15, 8.9), (-7, 11.9)
C. {(11.1, 7), (5.1, 4), (12.1, 5), (6.1, 7)}
D. {( square root of 1, -3), ( square root of 2, -4), (square root of 1, -5), (square root of 6, -7)}