The correct answer is A. The poles of the transfer function for a set of parameter values.
A root locus diagram is a graphical representation of the poles of a system’s transfer function as a function of a parameter. The poles of a system’s transfer function are the roots of the characteristic equation, and they determine the stability of the system. The root locus diagram can be used to analyze the stability of a system, to design controllers for a system, and to understand the effects of changes in system parameters on the system’s stability.
Option B is incorrect because the bandwidth of a system is determined by the system’s poles and zeros, not by the system’s parameters.
Option C is incorrect because the response of a system to a step input is determined by the system’s transfer function, not by the system’s parameters.
Option D is incorrect because the frequency response of a system is determined by the system’s transfer function, not by the system’s parameters.
Option E is incorrect because the root locus diagram does exhibit the poles of the transfer function for a set of parameter values.