Answer two questions about Systems A and B::
System A
{ -4x -6y =5
{3x + y = -4

System B
{-4x - 6y = 9
{-x - 5y =5

How can we get System B from System A?
A. Replace only the right-hand side of one equation with the sum/difference of the right- hand sides of both equations
B. Replace one equation with the sum/difference of both equations
C. Swap only the left-hand sides of both equations
D. Swap the order of the equations