Reviewing a 60-file migration pull request in one pass missed issues in the middle files. The team then tried reviewing each function separately: cost rose sharply and reviews still missed broken callers in other files. Which decomposition is best?

Answer: C — Per-file passes for local correctness, then an integration pass over findings and interface changes

Per-file granularity keeps attention focused without fragmenting context, and an explicit integration pass catches cross-file issues no single piece can see (c). (a) keeps attention dilution. (b) stays too fine and passes lossy summaries. (d) leaves most of the change unreviewed.