Iwill mark brainliest who ever hepls!

which set of ordered pairs represents a function?

a) {(0, 1), (1, 3), (1, 5), (2, 8)}

b) {(0, 0), (1, 2), (2, 6), (2, 8)}

c) {(0, 0), (0, 2), (2, 0), (2, 4)}

d) {(0, 2), (1, 4), (2, 6), (3, 6)}

Need on this geometry question. explain how you did it.

Find the directions in which the function increases and decreases most rapidly at upper p 0p0. then find the derivatives of the function in these directions. f(x,y)equals=x squared plus xy plus y squaredx2+xy+y2, upper p 0p0left parenthesis 1 comma negative 4 right parenthesis

Petes dog weighed 30 pounds it then lost 16% of it's weight how much did pete lose