SAT Text Structure and Purpose Question

Several sociologists have observed that the word "culture," though commonly used in academic literature, is an ultimately hazy concept—for example, Victoria Bonnell and Lynn Hunt have noted that “many critics have pointed to the vagueness of the concept of culture.” Does the concept of culture encompass knowledge, or laws, or both these things and others? For casual usage, such haziness is permissible—we know culture when we see it—but for researchers, a standardization of the term is called for if sociology is to truly progress. Which choice best describes the function of the underlined sentence in the text as a whole?