A large company has over 500 computers that currently stay powered on indefinitely. None of the systems are used after the company closes at 5 p.m. Which of the following would be the MOST effective way for the company to save on electricity usage？（）

1. A Set the computers for automatic log-off after one hour of inactivity.
2. B Institute a policy of either shutdown or sleep mode an hour after close. 正确答案
3. C Turn on the Wake on LAN functionality for all computers.
4. D Schedule all patching to be done during work hours.