If the lines x+2y−3=0x + 2y - 3 = 0x+2y−3=0, 2x+y−3=02x + y - 3 = 02x+y−3=0, and kx−y=0kx - y = 0kx−y=0 are concurrent, what is the value of kkk?
111
222
000
−1-1−1