AG Mechanics CDE Practice Exam 2026 – Comprehensive Test Prep Resource

During the compression stroke, both the intake and exhaust valves are closed to trap the air-fuel mixture in the combustion chamber before ignition. During the exhaust stroke, both valves are also closed as the piston pushes the remaining exhaust gases out through the open exhaust valve. Therefore, option A is correct as it correctly identifies the two strokes where both valves are closed. Options B, C, and D are incorrect because they do not represent the strokes where both valves are closed.