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)teenagers open the fast food outlets in the morning, close them at night, and keep them going at all hours in between