The amount of money an employee earns monthly before taxes, in dollars, after selling n products is $1,200 + $225n.

Which statement is correct?
A.
For every product sold, the employee's earnings increase by $1,425.

B.
For every product sold, the employee's earnings increase by $1,200.

C.
For every product sold, the employee's earnings increase by $975.

D.
For every product sold, the employee's earnings increase by $225.