For a recent year, McDonald's $($MCD$)$ company$-$owned restaurants had the following sales and expenses $($in millions$)$:

Assume that the variable costs consist of food and paper, payroll, $25\%$ of occupancy and other expenses, and $40\%$ of the general, selling, and administrative expenses.

a$.$ What is McDonald's contribution margin?

$

million

b$.$ What is McDonald's contribution margin ratio? Round to one decimal place.

$\%$

c$.$ How much would operating income increase if same$-$store sales increased by $$900$ million for the coming year, with no change in the contribution margin ratio or fixed

costs? Round your answer to the nearest tenth of a million $($one decimal place$).$

$

million