B. To multiply two matrices, we must first know 1. The number of columns in the first matrix is equal to the number of rows in the second matrix; 2. The number of rows of the new matrix is equal to that of the first matrix and the number of columns is equal to that of the second matrix. In fact, you can already choose the answer, because only B meets the requirements.

Say it carefully, as follows.

The first matrix:

[a 1 1，a 12，a 13

a2 1，a22，a23

a3 1，a32，a33]

The second matrix:

[b 1 1

b2 1

b3 1]

Multiply two matrices to get a new matrix with three rows and one column:

c 1 1 = a 1 1 * b 16+a 12 * b 2 1+a 13 * b 3 1

c 2 1 = a 2 1 * b 1 1+a22 * b 2 1+a23 * b 3 1

c 3 1 = a 3 1 * b 1 1+a32 * b 2 1+a33 * b 3 1

Applying this formula to the problem, we can find that the product of two matrices in option B is exactly equal to the sum of the prices of three models XYZ multiplied by the sales volume, that is, the total sales volume.