The velocity of sound is largest in:

Answer: Steel.

The speed of sound depends on the elastic properties (stiffness) and density of the medium, given by v = sqrt(E/rho), where E is the relevant elastic modulus and rho is the density. A more rigid (less compressible) medium transmits sound faster, and this stiffness effect dominates over density.

Solids are the most rigid media (highest elastic modulus), so sound travels fastest through them. Liquids are intermediate, and gases, being highly compressible with widely spaced particles, are the slowest. The general order is: solids > liquids > gases.

Comparing the given options: steel (a solid) ~ 5790 m/s, water (a liquid) ~ 1480 m/s, oil (a liquid) ~ 1300-1400 m/s, and air (a gas) ~ 343 m/s. Since steel is the only solid here, the velocity of sound is largest in steel.