Jill purchased her principal residence on January 1, Year 4 for $300,000. On January 1, Year 6, when it was worth $250,000, she turned it into a rental house. On January 1 Year 9, after depreciating the house $20,000, Jill sold it for $310,000. What is it's realized gain on the sale? O $30,000 O $10,000 O $20,000 O $50,000 O $80,000