At a price of $$2\mathrm{.}28$ per bushel, the supply of a certain grain is $7100$ million bushels and the demand is $7700$ million bushels. At a price of $$2\mathrm{.}35$ per bushel, the supply is $7500$ million bushels and the demand is $7600$ 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.

A$.$

B$.$

c$.$