Correct Answer : Option (C) : Three
Explanation : The given characteristic equation is: s^3 + 3s^2 + 4s + 1 = 0.
To find the number of roots, we need to create a Routh table, as shown below:
There are no roots and no significant changes in the RHS plane, as shown in the above table. Hence, all three roots lie in the LHS plane.