Which of the following DOES NOT characterize an equilibrium in the signalling model of educational attainment?

a.

Workers are paid a wage that is equal to their marginal revenue product.

b.

High productivity workers earn more than low productivity workers.

c.

Not all workers invest in the same amount of schooling.

d.

Firms' beliefs about the relationship between productivity and educational attainment are confirmed.

e.

None of the above.