Consider the following two subsets of \(\mathbb{C}\) : \[A=\left\{\frac{1}{z}:|z|=2\right\} \text { and } B=\left\{\frac{1}{z}:|z-1|=2\right\} \text { . }\] Then \(\qquad\) (a) \(A\) is a circle, but \(B\) is not a circle. \(\qquad\) (b) \(B\) is a circle, but \(A\) is not a circle. \(\qquad\qquad\) (c) \(A\) and \(B\) are both circles. \(\qquad\qquad\quad\) (d) Neither \(A\) nor \(B\) is a circle.