Billy Construction is constructing a new residential condominium building with 50 units. Construction costs during the construction period totaled $20,000,000 and was directly financed with a $20,000,000 loan from XYZ bank. Which of the following is true with respect to the capitalization of interest?

a. all the interest must be capitalized until the construction activity on the building is completed

b. all the interest must be capitalized until all the units are finally sold

c. taxpayer may stop capitalizing interest for each separate unit as each unit is sold

d. the interest expense is not required to be capitalized

e. all the interest must be capitalized until the loan is paid is repaid in full