For what value of kkk does the system {x+2y=32x+4y=k\begin{cases} x + 2y = 3 \\ 2x + 4y = k \end{cases}{x+2y=32x+4y=k have infinitely many solutions?
k=6k = 6k=6
k=3k = 3k=3
k=0k = 0k=0
k=−3k = -3k=−3