Which excerpt from Fast Food Nation best states a reason supporting the author’s claim that fast food restaurants follow the assembly line model? 
 A: Once an order has been placed, buttons light up and suggest other menu items that can be added.
 B: At Burger King restaurants, frozen hamburger patties are placed on a conveyer belt and emerge from a broiler ninety seconds later fully cooked.
 C: The McDonald’s operations manual today has ten times the number of pages and weighs about four pounds.
 D: Is incorrect