Which of the following is a direct example of resonance?

Resonance is a phenomenon where an oscillating system responds with maximum amplitude when the frequency of an external driving force matches the system's natural frequency.

Let's evaluate the options:

• A) bursting of an inflated balloon: This is due to excessive internal pressure exceeding the material's strength, not resonance.
• B) sound produced from a guitar: While a guitar's body acts as a resonator to amplify string vibrations, the general "sound produced" isn't the most direct or clear example of the effect of resonance compared to tuning a radio.
• C) tuning a radio receiver to a favourite station: This is a classic example of electrical resonance. When you tune a radio, you adjust its internal circuit (an LC circuit) so that its natural resonant frequency matches the frequency of the desired radio station's electromagnetic waves. This causes the circuit to oscillate with a large amplitude, amplifying that specific signal and allowing you to hear the station clearly.
• D) production of echoes: Echoes are caused by the reflection of sound waves off a surface, not by resonance.

Therefore, tuning a radio receiver is a direct application and representation of the resonance effect.

The correct option is C.

The answer is $\boxed{\text{C}}$.