The goal is to put the utility maximisation problem max x^2 +2*y^4 +3*ln(z) s.t. p*x +q*y +r*zw, -x0, -y0, -z0 into a form in which there are no parameters p, q, r, w in the constraints. The parameters p, q, r, w are all strictly positive, but no additional assumptions are made on these. A similar problem was solved in Tutorial 12.

Which variable(s) among x, y, z may be assumed positive for any p, q, r, w without loss of generality? Another way to ask this question is: which nonnegativity constraint(s) may be eliminated without loss of generality?

Select one:

a.

y or z may be assumed positive without loss of generality

b.

x or z may be assumed positive without loss of generality

c.

only z may be assumed positive without loss of generality

d.

only y may be assumed positive without loss of generality

e.

x or y may be assumed positive without loss of generality

f.

only x may be assumed positive without loss of generality

g.

any of x, y, z may be assumed positive without loss of generality