From the words or group of words lettered A to D, choose the word or group of words that best completes the sentence below. The order is that everyone must ...

Answer Details

The correct answer is "in". The sentence is discussing a rule or order about going to bed by midnight. To indicate the correct usage of time, the preposition "in" should be used to indicate a time frame within which an action must be completed. For example, "I will finish my work in an hour." Therefore, the correct sentence is "The order is that everyone must be in bed by midnight."