You are designing an empirical test of the hypothesis that school tracking (separating students into advanced and remedial streams) reproduces class advantage. Which research design will best support causal inference about institutional effects and why?

• A. A single cross-sectional survey asking students how they feel about tracking at one point in time with no controls, because subjective feelings provide definitive causal proof of structural reproduction.
• B. A content analysis of school slogans on gym walls alone, without linking those texts to enrollment data, because slogans capture the entire causal mechanism of tracking across decades.
• C. A longitudinal quasi-experimental design comparing cohorts before and after the introduction or removal of tracking within similar districts, controlling for student background, because it allows observation of changes attributable to the institutional policy over time while addressing selection bias.
• D. A laboratory experiment with randomized assignment of track labels to university students while ignoring actual school contexts and historical patterns, because lab conditions perfectly simulate complex social institutions.

Answer: (C)