A signal is said to be1. Deterministic if there is no uncertainty over the signal at any instant of time.2. Deterministic if it is expressible through a mathematical equation.3. Random or non-deterministic if there is uncertainty over the signal at the instant of time.4. Random or non-deterministic if it is not expressible through a mathematical equation.Which of the above statements are correct?

• A. 1, 2 and 3 only
• B. 1, 2 and 4 only
• C. 3 and 4 only
• D. 1, 2, 3 and 4