Find a Matrix a and a Column Matrix B That $$A B = \left[ \begin{array} { l } 840 \\650 \\870\end{array} \right]$$

Find a matrix A and a column matrix B that describe the following tables involving credits and tuition costs. Find the
matrix product AB, and interpret the significance of the entries of this product.
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A)
$$A B = \left[ \begin{array} { l } 840 \\650 \\870\end{array} \right]$$
Tuition for Student 1 is $\$ 840$ , tuition for Student 2 is $\$ 650$ , and tuition for Student 3 is $\$ 870$ .
B)
$$\mathrm { AB } = \left[ \begin{array} { l } 17 \\15 \\12\end{array} \right]$$
The number of credits for Student 1 is 12, the number of credits for Student 2 is 15, and the number of credi Student 3 is $12 .$
C)
$$\mathrm { AB } = \left[ \begin{array} { l } 940 \\800 \\620\end{array} \right]$$
Tuition for Student 1 is $\$ 940$ , tuition for Student 2 is $\$ 800$ , and tuition for Student 3 is $\$ 620$ .
D)
$$A B = \left[ \begin{array} { l } 12 \\17 \\15\end{array} \right]$$
The number of credits for Student 1 is 12 , the number of credits for Student 2 is 17 , and the number of credi Student 3 is $15 .$