Trong các ma tr?n sau, ma tr?n nà o là ma tr?n có d?ng b?c thang? \( A=\left[\begin{array}{llll}1 & 2 & 0 & 3 \\ 0 & 0 & \sqrt{\text { Time left 1:11:4 }} \\ 0 & 1 & 0 & 0\end{array}\right] \)
\[
\begin{aligned}
B & =\left[\begin{array}{llll}
0 & 2 & 2 & 1 \\
0 & 0 & 1 & 2 \\
0 & 0 & 0 & 0
\end{array}\right], C=\left[\begin{array}{llll}
1 & 1 & 2 & 4 \\
0 & 3 & 7 & 2 \\
0 & 0 & 1 & 1 \\
0 & 0 & 2 & 2
\end{array}\right], \\
D & =\left[\begin{array}{llll}
0 & 0 & 0 & 1 \\
0 & 0 & 0 & 0 \\
0 & 0 & 0 & 0 \\
0 & 0 & 0 & 0
\end{array}\right], E=\left[\begin{array}{llll}
1 & 4 & 2 & 1 \\
2 & 3 & 0 & 0 \\
1 & 0 & 0 & 0
\end{array}\right], F=\left[\begin{array}{llll}
1 & 2 & 3 & 1 \\
0 & 4 & 4 & 2 \\
0 & 0 & 0 & 1
\end{array}\right]
\end{aligned}
\]
a. Ma tr?n \( A, D, E \)
b. Ma tr?n B, C, F
c. Ma tr?n D, E, F
d. Ma tr?n B, D, F