3. Answer "yes" or "no" for the following questions. (a). RGA is a useful metric to assess the process interaction and stability of a decentralized control system. (b). For a 2x2 decentralized control system, a negative relative gain implies a closed-loop unstable decentralized control system. (c). For a 3x3 decentralized control system, a negative relative gain implies a closed-loop unstable decentralized control system. (d). In decentralized control system design, a negative NI index presents a more challenging controller design problem compared with those with negative relative gain. (e). If AR frequency response curve of the sensitivity function for controller design 1 lies below that of controller design 2, it can be concluded that the controller design 2 will exhibit better performance than that obtained by the controller design 1 based on the NP criterion. (f). A control system designed to satisfy the RP criterion will also achieve NP requirement. (g). A control system designed to satisfy the RP criterion will also achieve RS requirement. (h). A control system designed to satisfy the NP criterion will also achieve RS requirement. (i). Z-transform of zero-order hold is equal to 1. (j). A digital controller with a positive real pole gives less aggressive control action compared with that obtained by a digital controller with negative real pole