Consider a family of circles which are passing through the point $(-1, 1)$ and are tangent to $x-axis$. If $(h, k)$ are the coordinates of the centre of the circles, then the set of values of $k$ is given by the interval :

Question

( A ) $k \leq 1/2$
( B ) $k \geq 1/2$
( C ) $ 0 < k < 1/2$
( D ) $-1/2 \leq k \leq 1/2$