1272 questions split across the People (369), Process (802) & Business Environment (101) domains — including 96 match-the-pairs and 9 put-in-order exercises. Pick a domain to drill one ECO area, or "All domains" for a mixed set. Set C comes from 10 full practice exams with PMI ECO domain tags — every answer key was hand-verified against the source explanation. Earlier sets carry PMBOK page citations or were hand-rewritten from a purchased bank — verify any answer that surprises you.