Step$-$by$-$Step Guide to Drawing the Graph:

Set Up the Axes:

Label the Y$-$axis as "Price$/$Cost$"($in dollars$).$

Label the X$-$axis as "Quantity" $($the number of iPhones produced and sold$).$

Draw the Demand Curve $($D$)$:

Begin at the top of the Y $-$axis and draw a downward$-$sloping line to the right.

Label this line D $($Demand$).$ The line should be steep enough to indicate Apple's strong brand loyalty, where price decreases only slightly as quantity increases.

Draw the Marginal Revenue Curve $($MR$)$:

Start at the same price level as the demand curve but draw this line steeper and below the demand curve.

The MR curve should never intersect the demand curve, but instead, be positioned below it and slope downward.

Label this curve MR $($Marginal Revenue$).$ It will be steeper than the demand curve because the firm must reduce the price for all units to sell additional units.

Draw the Marginal Cost Curve $($MC$)$:

Draw an upward$-$sloping curve starting from a lower point on the X$-$axis.

Label this curve MC $($Marginal Cost$).$ It should slope upward, showing increasing production costs with more output.

Draw the Average Total Cost Curve $($ATC$)$:

Draw a U$-$shaped curve that starts higher on the Y$-$axis, slopes downward initially $($showing economies of scale$),$ then starts to slope upward $($reflecting diseconomies of scale$).$

Label this curve ATC $($Average Total Cost$).$

The ATC curve should intersect the MC curve at its lowest point.

Determine the Profit$-$Maximizing Output:

Find the point where the MR curve intersects the MC curve. This is the output level $($quantity$)$ where Apple maximizes its profit.

Label this intersection as $Q^{**}($Profit$-$maximizing quantity$).$

Determine the Price:

From the point $Q^{**}$ on the X $-$axis, draw a vertical line upward to the Demand curve.

Label the price at this point as $P=$$$999($the price Apple charges for the iPhone $15$ Pro$).$

Label the Profit Area:

The difference between the price $($$$999)$ and the ATC at $Q^{**}($the quantity produced$)$ represents Apple's per$-$unit profit.

The area between the price and thr ${?}^{TT}$ TC curve, bounded by the quantity $Q,$ shows the total profit.