Anthony entered into a long-term construction contract in year 3. The total profit of the contract is $80,000 and does not change over the life of the contract. The contract will be completed in year 5. The contract is 20%. and 70% complete at the end of years 3 and 4, respectively. What is the alternative minimum tax adjustment required in year 4?

a. $16,000 

b. $40,000

c. $56,000

d. $80,000