The Boeing Company buys $3 million worth of steel, $2.5 million worth of computer hardware and software, and $1 million worth of mechanical tools to manufacture a certain model of aircraft. Boeing sells this particular model of aircraft at $10 million. The value added by Boeing is equal to:A)$3.5 million.B)$16.5 million.C)$13 million.D)$15.5 million.