Q.

Let A={z:1|z-(1+i)|2} and B={zA:|z-(1-i)|=1}. Then B:

1 is an empty set  
2 contains exactly two elements  
3 contains exactly three elements  
4 is an infinite set  

Ans.

(4)

A={zC:1|z-(1+i)|2}

B={zA:|z-(1-i)|=1}          AB has infinite set.