ry reduces consumer surplus by $100, increases tariff revenue by $50, and increases producer surplus by $20, then which of the following is INCORRECT?...

If a Tariff in a small country reduces consumer surplus by $100, increases tariff revenue by $50, and increases producer surplus by $20, then which of the following is INCORRECT?

a. National welfare falls by $30

b. National welfare falls by $50

c. Deadweight loss is $30

d.The protection cost is $30