Matrix addition can only be performed on matrices of the same size.
This means that you can only add matrices if both matrices are m × n.
For example, you can add two or more 3 × 3, 1 × 2, or 5 × 4 matrices. You cannot add a 2 × 3 and a 3 × 2 matrix, a 4 × 4 and a 3 × 3, etc.
The number of rows and columns of all the matrices being added must exactly match.
Therefore, the answer is letter D - These two matrices cannot be added.