In case of type-1 system steady state acceleration is

unity
infinity
zero
10

The correct answer is C. zero.

A type-1 system is a first-order system with a pure time delay. The steady state response of a type-1 system is a constant value, which means that the acceleration is zero.

Option A is incorrect because the steady state response of a type-1 system is a constant value, not unity.

Option B is incorrect because the steady state response of a type-1 system is a constant value, not infinity.

Option D is incorrect because the steady state response of a type-1 system is a constant value, not 10.