A monopolist can produce two goods of differing qualities (z₁ and z₂) and sells to two types of consumers with differing willingness to pay for quality. Assume indirect utility of both types of consumers is given by =()Vi=i(zz_i)p, for i =1,2; where is reservation quality of consumer i and ₁ > ₂. Which statement best describes the 'incentive compatibility constraint' for type 1 consumers?

a.

1(11)12(21)11(z1z_1)p12(z2z_1)p1

b.1(11)12(22)21(z1z_1)p12(z2z_2)p2

c.

1(11)11(21)11(z1z_1)p11(z2z_1)p1

d.

1(11)11(21)2