1. The low pitch stop on a constant-speed propeller is usually set so that A. the engine will turn at its rated takeoff RPM at sea level when the throttle is opened to allowable takeoff manifold pressure. B. maximum allowable engine RPM cannot be exceeded with any combination of manifold pressure, altitude, or forward speed. C. the limiting engine manifold pressure cannot be exceeded with any combination of throttle opening, altitude, or forward speed.