At a price of $2.22 per bushel, the supply of a certain grain is 7500 million bushels and the demand is 7800 million bushels. At a price of $2.31 per bushel, the supply is 7900 million bushels and the demand is 7700 million bushels. (A) Find a price-supply equation of the form p = mx + b, where p is the price in dollars and x is the supply in millions of bushels. (B) Find a price-demand equation of the form p = mx + b, where p is the price in dollars and x is the demand in millions of bushels. (C) Find the equilibrium point. (D) Graph the price-supply equation, price-demand equation, and equilibrium point in the same coordinate system. (A) The price-supply equation is p= (Type an exact answer.) (B) The price-demand equation is p= (Type an exact answer.) (C) The equilibrium point is (Type an ordered pair. Type an exact answer. Use integers or decimals for any numbers in the expression.) (D) Choose the correct graph below. O A. O B. Ap O C. 7000 8000 7000 3000 7000 8000