The best edit to improve the use of punctuation in sentence 16 from paragraph 5 is:
A. Add a comma after viewpoints.
The corrected sentence would read: "Moreover, the echo chamber effect of social media algorithms can actually limit exposure to diverse viewpoints, reinforcing existing biases and misconceptions."
This insertion clarifies that "reinforcing existing biases and misconceptions" is an additional clause explaining the preceding idea about limiting exposure to diverse viewpoints.