Vector 10 5 was transformed to 50 25. What was the transformation?

D is the correct answer.

Step-by-step explanation:

5* [10 ; 5] = [50 ; 25].

by the way the semi column stands for that the next elememt is on the next row.

for A and C choices, they are wrong since we can't multiply two matrices even if the number of columns of the first matrix is equal to the number of rows of the second.