The vectors v⃗ 1=⎡⎣⎢1−70⎤⎦⎥, v⃗ 2=⎡⎣⎢−25−4⎤⎦⎥, v⃗ 3=⎡⎣⎢0−18k⎤⎦⎥ form a basis for r3 if and only if k≠
a) 0
b) -1
c) 1
d) Any real number