Answer:
4. Revise “finally” at the beginning of Sentence 5.
Step-by-step explanation:
Finally should be revised as its inconsistent with the order with which the writer has placed his points. If he had arranged the points with connectors such as firstly, secondly, then finally can be added to cap it all.
"for example" is correct because the trend of what mentioned before requires an analogy to buttress on the point
"However" is also correct which means "on the other hand". It depicts the other side of the thoughts that has been raised earlier.