Explanation:

- The speed of sound depends on the medium. It travels fastest in solids, then liquids, and slowest in gases.

- Air: Sound travels slowest here, about 343 m/s at room temperature.

- Water: Faster than air, approximately 1482 m/s.

- Steel rod: Sound rips through steel at around 5000 m/s or more—much faster than in air or water.

- Kerosene: As a liquid, it transmits sound faster than air but slower than steel, roughly close to water's speed.

Correct answer: Option 3 - Steel rod