3=4m+ b
-1=3m+b
m=4
plug in to either equation,
3=16+ b
b=-13
Thus, C would be the answer.
ANSWER
The multiplication, CA is defined, and its dimension is 3×2
EXPLANATION
Matrix A is a 2x3 matrix.
Matrix C is a 3×2 matrix.
The product of the two matrices , CA, is defined if and only if the inner product of their dimension are the same.

The inner products are the same.
Hence the matrix multiplication, CA is defined and its dimension is the outer products.

Five hundred and sixty two divided by seven would be,
=80.28