George purchased a lot in 2010 for $2,000,000 (he paid $1,200,000 and borrowed $800,000 from a bank), in the same year he built a small office building on the lot at a cost of $500,000. In 2015 he made improvements for $50,000. George sold the building for $3,000,000 in 2023. George's approximate depreciation was $50,000.

a) What was his basis?

b) Amount of gain realized?

c) Amount of gain recognized?