Monroe Construction Company uses the percentage-of-completion method of accounting. In 2015, Monroe began work on a contract it had received, which provided for a contract price of $15,000,000. Other details are as follows: cost incurred during 2015 is $7,200,000; estimated cost to complete at December 31, 2015 is $4,800,000; billings during the year for 2015 amount to $6,600,000; and collections during 2015 amount to $3,900,000. What should be the gross profit recognized in 2015?
A $600,000
B $7,800,000
C $1,800,000
D $3,000,000