Answer:
B). Background Information.
Step-by-step explanation:
Background information is described as the information that readers require for a proper understanding of the topic.
The element that is missing from the given paragraph is the 'background information' as the author is not providing any description to reveal that in what context is he introducing the topic i.e. 'limits to freedom of speech.' The hook or the attention grabber sentence is immediately followed by the background information, but here the author fails to provide any significance or historical value that can comprehend readers' understanding of the topic. Thus, option B is the correct answer.