Literary criticism is referred to as the learning, assessment, and analysis of literary works. Contemporary literary criticism often depends on the literary theory, which is the idealistic discussion of literature's objectives and techniques.
A critic is the one who offers a thorough review of arts or ethnicity and can focus on one of a variety of genres in the vast gamut of literature. These evaluations can emerge in the media, newspapers, or online. Moreover, a literary critic can be called audiences’ advocate, who provides readers with information about a new creation or book.
A critic evaluates for the general public and cannot suggest biased statements to prove his/her theory. He also has nothing to do with the financial progress made by a book.
So, the correct answer here, considering the role of a critic is: B; as a social commentator, who explains what a book says about people in general.