Which of the following statements is true about time-invariant systems?

A) Their response changes over time.

B) Their response remains the same regardless of when the input is applied.

C) They can only be linear systems.

D) They are not suitable for DSP applications.

Answer: B) Their response remains the same regardless of when the input is applied.

Explanation: Time-invariant systems produce the same output for a given input regardless of when that input is applied. This property is crucial for consistent system behavior in signal processing.