A unity feedback control system has an open-loop transfer function \(G\left( s \right) = \frac{K}{{s\left( {s + 1} \right)\left( {s + 2} \right)\left( {s + 3} \right)}}\) The centroid of the asymptotes in root-locus will be _______
1
-1
2
-1.5
3
Zero
4
2
5
- 3