Let $$A = \begin{bmatrix} 1 & 3 & -1 \\ 2 & 1 & \alpha \\ 0 & 1 & -1 \end{bmatrix}$$ be a singular matrix. Let $$f(x) = \displaystyle\int_0^x (t^2 + 2t + 3)\,dt$$, $$x \in [1, \alpha]$$. If M and m are respectively the maximum and the minimum values of $$f$$ in $$[1, \alpha]$$, then $$3(M - m)$$ is equal to :

A

64

B

68

C

72

D

76