As is shown by the example of college dropout Bill Gates, more education does generally not pay off

When a monopolist engages in perfect price discrimination,

A) the marginal revenue curve lies below the demand curve. B) the demand curve and the marginal revenue curve are identical. C) marginal cost becomes zero. D) the marginal revenue curve becomes horizontal.

Ideal randomized controlled experiments in economics are

A) often performed in practice. B) often used by the Federal Reserve to study the effects of monetary policy. C) useful because they give a definition of a causal effect. D) sometimes used by universities to determine who graduates in four years rather than five.