John owns real estate with a fair market value of $1 million in which he has a basis of $250,000. In 2006, John sold the property to his son, Junior, for $1 million. However, due to John's cash flow problems, Junior must pay the $1 million plus interest over 5 years.In 2013, Junior sells the property for $2 million. What is Junior's gain on the sale of the real estate?

a. $750,000

b.$1 million.

c.$1,750,000.

d.Cannot be determined.