Which of the following statements is true about linear systems?

A) They can produce non-linear outputs for linear inputs.

B) They obey the principle of superposition.

C) They are always stable.

D) They cannot be represented mathematically.

Answer: B) They obey the principle of superposition.

Explanation: Linear systems adhere to the principle of superposition, meaning that the response of the system to a combination of inputs is equal to the sum of the responses to each individual input.