The question is asking for indicators or displays with which we can monitor the engine. This is not very specific, as an engine's performance or its health can be monitored, so we will assume both. To go through each option:

• 1. "Hydraulic Pressure"
  • We do not know exactly what pressure they are referring to, perhaps they are referring to the hydraulic pressure from the engine driven hydraulic pump, in which case, that is not a useful way to monitor the engine health or performance, as it usually maintains a constant pressure, and there are varying demands of the hydraulic system as well.
• 2. "Oil Temperature" - Correct
  • As with any engine, oil temperature is a vital indicator of engine health.
• 3. "Chip Detector Caution Light" - Correct
  • A chip detector is a small magnetic probe that exists in the oil return line, before any scavenge pump and filter (if present). It will collect any small bits of ferrous material (which stick to the magnet), and if a build-up occurs, it is very indicative of internal engine damage. Some can detect a build-up remotely, without being removed, and will notify the flight deck via a light or some other indication. This is of course an engine health monitoring device.
• 4. "Fuel Filter Bypass Indication" - Incorrect
  • The fuel filter is used to make sure no large particulate contaminants within the fuel can flow into the engines, causing damage to the components. If the fuel filter becomes blocked though, there is a bypass line that allows unfiltered fuel into the engine (It is better to have potentially contaminated fuel than no fuel at all). If the fuel filter is blocked and the bypass line has to be used, an indication of this will be sent to the flight deck, and that tells the pilots that unfiltered fuel is being used. This might require careful engine monitoring and a maintenance inspection on the ground, but in itself this is not telling us anything about the engine, so is NOT an engine monitoring indication.
• 5. "Fuel Flow" - Correct
  • Fuel flow monitoring is used to monitor both engine health and (moreso) performance. It is also used for monitoring the engine start process.
• 6. "Oil Pressure" - Correct
  • As with all engines, oil pressure is a vital indication for the pilots to have, as oil is required for the engine to run without causing itself serious damage. Oil pressure indications tell us that the oil pumps are working correctly.
• 7. "Outside Air Temperature Display"
  • The OAT, whilst important to know for operations, is not a method of monitoring an engine.