Polychromasia Company sold inventory costing $30,000 to its subsidiary, Simply Colorful, for double its cost in 2009. Polychromasia owns 80% of Simply Colorful. Simply resold $50,000 of this inventory for $60,000 to outsiders in 2009. How much unrealized profit exists at the end of the year?

please explain answer

A. 20,000

B. 10,000

C. 8,000

D. 5,000