Consider a second order system whose state space representation is of the form $x^{}=Ax+Bu.$

Where $A=\left[\begin{array}{cc}{a}_{11}& a_{12}\\ a_{21}& a_{22}\end{array}\right],B=\left[\begin{array}{c}{b}_1\\ b_2\end{array}\right]$ and $x_1(t)=x_2(t).$ From the information given which one of the following options best describes the system?

a$.$ Controllable

b$.$ Observable

C$.$ None of the given options

d$.$ Uncontrollable