A first-order system has a time constant of 2 seconds and is subjected to a unit step input. The system gain is unity, then1.The output reaches approximately 63 percent of its final value at 2 seconds.2.The steady-state value of the output is equal to1.3. The response is exponential in nature and does not exhibit oscillations.4.The output reaches 95 percent of final value in about 2 seconds.Which of the above statements is/are correct?