Answer:
The correct answer is The man who sat beside me at lunch, speaks French.
Explanation:
Relative clauses are sentences with<u> relative pronouns</u> (who, which, whose, that) used to define and identify a thing or person that <u>has already been mentioned before and we want to add more information.
</u>
To understand <u>whether it is necessary to add a comma or not</u>, you must ask yourself if the information you are adding is <u>extra or necessary</u>.
In this case, <em>"The man who sat beside me at lunch, speaks French."</em> The fact that he speaks French <u>is not relevant</u> with respect to the person to whom "<em>who</em>" is referring.
A necessary information would be <em>“sat beside me at lunch”</em>, since without that information it could be talking about any man.
I think c bc it does seem like he is sick
