Anton purchases a building on May 4, 2003, at a cost of $270,000. The land is properly allocated $30,000 of the cost. Anton sells the building on October 18, 2020, for $270,000. What is his gain or loss on the sale if he uses the regular MACRS system and the building is

a. An apartment building?

b. An office building?

c. How would your answers to parts a and b change if Anton makes a straightline election on the building? Explain.