Which display includes oil temperature and oil pressure readings?

The engine/systems display is the correct choice because it is specifically designed to provide critical information about the engine's performance and health, including parameters such as oil temperature and oil pressure readings. This display consolidates essential data needed for monitoring engine systems, allowing pilots to quickly assess operational status and address any anomalies.

The primary display typically shows flight-related data, including altitude, airspeed, and navigation information, but does not necessarily provide detailed engine parameters. The diagnostic display is usually reserved for troubleshooting and error codes rather than real-time performance data. The alternate display may serve as a backup to the primary display and can reflect some vital information, but its primary function is not to give comprehensive engine data. Thus, the engine/systems display is the most appropriate source for oil temperature and oil pressure readings.