50. The current price of compact discs, which are traded in perfectly competitive markets, is $10. A $1 per unit tax is levied on the discs. Annual record sales decline from five million to four million as a result of the tax. Assuming that the income effect of the tax-induced price change is negligible, the excess burden of the tax will be:
(A) $500,000 per year.
(B) $1 million per year.
(C) $2 million per year.
(D) $2.5 million per year.