Following statements are given for control systems:a) Transfer function is a ratio of Laplace transform of output to input considering initial conditions are zero.b) Transfer function is a ratio of Laplace transform of output to input irrespective of initial conditions.c) Error signal is a difference of the reference signal and the feedback signal.d) In the signal flow graph the input is divided by transmittance to obtain the output signal.Which of the following is correct?

• A. and c) are correct
• B. and c) are correct
• C. and d) are correct
• D. and d) are correct