need help on Part D. please.

Modern Artifacts can produce keepsakes that will be sold for $80 each. Nondepreciation fixed costs are $1,000 per year, and varia costs are $60 per unit. The initial investment of $3,000 will be depreciated straight-line over its useful life of 5 years to a final value zero, and the discount rate is 10%. (For all the requirements, do not round intermediate calculations. Round your answer to the nearest whole number.) a. What is the accounting break-even level of sales if the firm pays no taxes? b. What is the NPV break-oven level of sales if the firm pays no taxes? c. What is the accounting break-even level of sales if the firm's tax rate is 40% ? d. What is the NPV break-even level of saies if the firm's tax rate is 40%