Martha McDonald purchased an office building in 1999 for $630,000. In 2019, she sells the building for $950,000. Over the years, she had replaced the windows and doors at a cost of $60,000, repainted the exterior at a cost of $15,000, and installed an elevator at a cost of $90,000. Martha had taken straight line depreciation on the building for 20 years, for a total of $400,000.

a. What is Martha's basis in the building at the time of the sale?

b. What is her realized gain?

c. What is her recognized gain?