In 2010,Father Sold Land to Son for $75,000 Cash and an Installment

In 2010,Father sold land to Son for $75,000 cash and an installment note for $225,000.Father's basis was $120,000.In 2011,after paying $24,000 interest but nothing on the principal,Son sold the land for $300,000 cash.As a result of the second disposition,what gain must Father recognize in 2011?

A) $180,000.
B) $135,000.
C) $120,000.
D) $60,000.
E) None of the above.