Answer:
Based on the options provided, the reason close-ups of people are likely used in the video is:
OB. To show students how to duck and cover.
Close-ups of people in the video are likely used to provide a clear and detailed demonstration of the correct way to perform the "duck and cover" procedure, showing students the proper technique for their safety during certain situations, such as in the event of a threat.
Step-by-step explanation: