For a type 1 system, the steady-state: A. error for a step input is always zero B. error for a velocity input is always zero C. input for acceleration input is always non-zero D. (a) and (c) E. None of the above

The correct answer is: A.

A type 1 system is a system that has a zero steady-state error for a step input. This means that the output of the system will eventually reach the same value as the input, even if there is some initial error.

Option B is incorrect because a type 1 system does not necessarily have a zero steady-state error for a velocity input. In fact, the steady-state error for a velocity input will be non-zero if the system has a time delay.

Option C is incorrect because a type 1 system does not necessarily have a zero steady-state error for an acceleration input. In fact, the steady-state error for an acceleration input will be non-zero if the system has a time delay and a transport delay.

Option D is incorrect because only option A is correct.

Option E is incorrect because option A is correct.