Your Answer is

Correct Answer is A

Explanation

Usually, two binary linear equations can already determine the only solution of x and y, but the question stem says that for the following equations, all x and y satisfying 2x-3y=6 are fine. Observation shows that 2x-3y=6 in the question stem is actually equivalent to 18x-27y=54, so if 6x+ky=-2k is also equivalent to the above two formulas, it can explain why the equation system does not Get definite x,y values. So k=-9.