Assess students' ability to evaluate and compare the effectiveness and limitations of the Beale–Kato–Majda, Prodi–Serrin, and Serrin-type criteria in diagnosing finite-time singularity (blow-up) versus guaranteeing global regularity for 3D incompressible Navier–Stokes and Euler flows. The quiz should probe understanding of the hypotheses, functional settings (e.g., L^p, BMO, Sobolev), scaling and sharpness of the criteria, known conditional regularity results and counterexamples, differences between viscous and inviscid cases, and implications for ongoing research directions.