Which statement best expresses the octane requirement?

Which statement best expresses the octane requirement?

• A. A maximum of 91 octane.
• B. Octane must be exactly 91.
• C. Octane must be above 95.
• D. A minimum of 91 octane.

Answer: (D)

The main idea is that octane requirement is about the minimum fuel quality needed for the engine to run properly. Saying you need a minimum of 91 octane communicates that any fuel with 91 octane or higher will prevent knocking and allow normal operation. Using a lower-octane fuel risks detonation or reduced performance, which is why the other phrasings don’t fit: a maximum would wrongly limit higher-quality fuels, an exact value imposes an unnecessary restriction, and stating you must be above 95 implies a stricter requirement than necessary. In practice, you should use fuel that meets or exceeds the specified minimum octane to keep the engine running reliably.

The main idea is that octane requirement is about the minimum fuel quality needed for the engine to run properly. Saying you need a minimum of 91 octane communicates that any fuel with 91 octane or higher will prevent knocking and allow normal operation. Using a lower-octane fuel risks detonation or reduced performance, which is why the other phrasings don’t fit: a maximum would wrongly limit higher-quality fuels, an exact value imposes an unnecessary restriction, and stating you must be above 95 implies a stricter requirement than necessary. In practice, you should use fuel that meets or exceeds the specified minimum octane to keep the engine running reliably.