Question

E = [1 2] A = [3 0] [2 -1]

Answer 1

You know the factor of 2 will make the result have even numbers. Thus C and D are immediately eliminated. To tell whether the answer is A or B, you only need to find the second number.
.. 2*(1*0 +2*(-1)) = -4

The appropriate selection is ...

B. [14 -4]