Answer:
B. They could stop working when the boss went home.
Step-by-step explanation:
The white-collar workforce may operate from behind a desk, while the working class person of blue-collar gets his hands dirty doing manual work or working in a manufacturing unit. White-collar jobs referred mostly to office jobs, so typically they end at a fixed time, on the other hand, blue-collar jobs are service-oriented which can be performed whenever needed, so they're not as flexible. Therefore, as most offices have fixed times, white-collar workforce could stop work when their bosses stop.