The correct answer is: A. Transient response
The transient response is the initial response of a system when the input is changed. It is the time it takes for the system to reach a steady state, where the output is equal to the input.
The error response is the difference between the output and the input. It is a measure of how well the system is following the input.
The dynamic response is the overall response of a system to a change in the input. It includes both the transient response and the steady-state response.
In conclusion, the transient response is the initial response of a system when the input is changed. It is the time it takes for the system to reach a steady state, where the output is equal to the input.