Options for both are Knight/Knave/Can't Tell. Thanks!

The Island of Knights and Knaves has two types of inhabitants: Knights, who always tell the truth, and Knaves, who always lie. As you are exploring the Island of Knights and Knaves you encounter two people named A and B. A tells you of B and myself, exactly one of us is a Knight. B tells you "A is a Knave". Determine the nature of A and B, if you can. A is a B is a