Concept: The question tests on concepts of equations
Solution:
For any 2 equations of the for a1x + b1y = c1 and a2x + b2y = c2, we get a unique solution when a1/a2≠b1/b2
Therefore in the system of equations given, we get a unique solution when k/4≠1/k
Solving, we get k^2≠4, or k≠±2 which is the same as |k| ≠ 2
Option C