Which answer has a correct first step for this system: 3x + 3y = 3 y = 3x + 5

A. Free sha vaca doo

B. The variable is already isolated for y, so we substitute it in the first equation and solve for x 3x + 3(3x + 5) = 3

C. The variable is already isolated for y, so substitute it in th second equation a solve for x y = 3(3x + 3y) = 3

D. The variable is already isolated so weve already solved the system​