2. Consider the block diagram shown below. The third-order process shown is controlled by a simple proportional controller. R(s) I(s) X(s) 4 K (25+1) (35+1) + N(S) 0.25 + (a) (20%) What range of permitted values for the proportional gain K. may be employed? (b) (20%) Estimate the percentage offset in the response signal that would be observed for a unit step change in the set-point if the maximum allowed value for the proportional gain was employed (note that sN(s) 0 as s0). (c) (10%) Describe an effective way of eliminating this offset, in terms of the controller's specification. (d) (40%) Prepare a root-locus plot for this system