5. The woman's problem is that the scheduled lecturer canceled giving a special to give a speical lecture in her class.
The woman suggests two possible solutions to the problem. The first solution is to show her students a documentary on the same topic. The second suggestion is to prepare class materials for a normal class.
I think the second suggestion is better for her. (Mention "This is because~") Her class is behind schedule. So doing a normal class will be a good chance to catch up on the original schedule. Also she has a free time to prepare class materials. If she shows students the documentary, she will have trouble handling the lagged schedule in the future.
For these reasons, I would recommend the second option for her.
* 두 번째 이유를 선택한 점에서, 장점을 보다 서술해주실 수 있어야 합니다.
또한 documentary를 보게 됨으로써, 생기게 되는 단점을 하나 더 언급하여 주세요.