Correct Answer : Option (A) : Unstable
Explanation : The given characteristic equation is: s^4 + 5s^3 + 3s^2 + 6s + 5 = 0. We first need to find the roots by creating the Routh's array table.
Routh's array table is shown below:
In the first column of the above table, we have two sign changes. It means that two roots are in the RHS plane. Hence, the system is unstable.