From the words or group of words lettered A to D, choose the word or group of words that best completes each of the following sentences: The family............

Answer Details

The sentence is in the past tense, indicating that the action occurred before now. Therefore, the best option is "was having," as it indicates an action that was in progress at a specific time in the past. The correct sentence should read, "The family was having dinner when we knocked at the door."