Please please help me!!
solve the system of equations.
{ x= 3y + 4
{3x - 9y = 12

Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. There is one solution. The solution of the system is __ ( simplify your answer. Type an ordered pair.)
B. The solution set of the system {(x,y)| x = 3y+4}.
C. The solution set is ∅.