The State of New Porkswick Is One of Ten States

The state of New Porkswick is one of ten states in the democratic nation of Fatlandia.Each state has ten thousand residents.Although incomes vary,each Fatlandian pays a tax equal to the total cost of all government projects divided by the number of residents in the country.Fatlandia currently has one army base in each of two states and is considering establishing some new ones.An army base adds $250,000 to a state's local economy each year.The total cost of one army base is estimated to be $1,000,000 per year.The increased security of having additional army bases equals $10,000,000 - (3,000,000 * the number of bases) per year.
The marginal benefit of adding a third army base equals the local marginal benefit of $250,000 plus ______,for a total of _______.

A) $1,000,000;$1,250,000
B) -$2,000,000;-$1,750,000
C) -$1,000,000;-$750,000
D) $7,000,000;$6.750,000