Find $a, b, c$, and $d$ so that $\left[\begin{array}{ll}a & b \\ c & d\end{array}\right]+\left[\begin{array}{rr}6 & -6 \\ 0 & 4\end{array}\right]=\left[\begin{array}{ll}4 & -1 \\ 6 & -8\end{array}\right]$.

Select the correct choice and, if necessary, fill in the answer box to com
A. $\left[\begin{array}{ll}a & b \\ c & d\end{array}\right]=$ (Simplify your answer.)
B. There is no solution.

Step 1 ：The problem is asking to find the values of $a, b, c$, and $d$ in the matrix $\left[\begin{array}{ll}a & b \\ c & d\end{array}\right]$ such that when it is added to the matrix $\left[\begin{array}{rr}6 & -6 \\ 0 & 4\end{array}\right]$, the result is the matrix $\left[\begin{array}{ll}4 & -1 \\ 6 & -8\end{array}\right]$.

Step 2 ：In matrix addition, corresponding elements in the matrices are added together. So, we can set up the following equations based on the given matrices: $a + 6 = 4$, $b - 6 = -1$, $c + 0 = 6$, and $d + 4 = -8$.

Step 3 ：Solving these equations, we find that $a = -2$, $b = 5$, $c = 6$, and $d = -12$.

Step 4 ：Therefore, the matrix $\left[\begin{array}{ll}a & b \\ c & d\end{array}\right]$ is $\left[\begin{array}{ll}-2 & 5 \\ 6 & -12\end{array}\right]$.

Step 5 ：Final Answer: \(\boxed{\left[\begin{array}{ll}-2 & 5 \\ 6 & -12\end{array}\right]}\)