# Let $A =\left[\begin{array}{rrr}1 & -2 & \alpha \\ \alpha & 2 & -1\end{array}\right]$ and $B =\left[\begin{array}{rr}2 & \alpha \\ -1 & 2 \\ 4 & -5\end{array}\right], \alpha \in C$. Then the absolute value of the sum of all values of $\alpha$ for which $\operatorname{det}(A B)=0$ is : (A) 3 (B) 4 (C) 2 (D) 5

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Let $A =\left[\begin{array}{rrr}1 & -2 & \alpha \\ \alpha & 2 & -1\end{array}\right]$ and $B =\left[\begin{array}{rr}2 & \alpha \\ -1 & 2 \\ 4 & -5\end{array}\right], \alpha \in C$. Then the absolute value of the sum of all values of $\alpha$ for which $\operatorname{det}(A B)=0$ is :

(A) 3

(B) 4

(C) 2

(D) 5