Why Have Sociologists, at Times, Been Critical of Jonathan Kozol's

Why have sociologists, at times, been critical of Jonathan Kozol's findings on public schools in his work Savage Inequalities?

A) Schools are not integral to the functioning of society and are, therefore, not worthy of empirical study.
B) Young students cannot be trusted as respondents for sociological studies.
C) Poor students are likely to lie about their educational experiences to fit into normative constructions of what it means to be educated.
D) He had no systematic way in which he chose the schools he studied, which allowed for selection bias.