Consider the following functions.

G(x,y) =x1/2- y

H(x,y) = (4x+2y)2

L(x,y) =x + 3 y1/2

U(x,y) =x1/4y1/2

W(x,y) = ln(x) + ln(2y) + 20

Z(x,y) =min(3x ,y)

Select the function(s) which can be the "objective function" in the constrained maximization problem where the constraint is ax + by = 20, a>0 and b>0, and such that the Method of Lagrange can be used to find the complete solution to the problem.

a.

H

b.

None.

c.

Z

d.

U

e.

G

f.

L

g.

W