I don’t want you to get this wrong but I think it is C.
A good topic sentence is very clear, focused on the topic, directly relates the thesis, summarizes the main points of that paragraph, and strongly supports a claim.
Answer:
Print and blackboards/whiteboards
Explanation:
When objects are put in print you can revisit certain areas where you may be confused and ask clear questions about that part.
Blackboards and whiteboards allow you to see everything in front of you and point to certain areas.
It is in the present participle.
The "Can't see it," paragraph :) the night is personified to 'press' it's blackness upon the yatch!