You cannot answer that question with "I don't" or even "I don't know" because existence is axiomatic. Any answer you give to this question (or any other) subsum

You cannot answer that question with "I don't" or even "I don't know" because existence is axiomatic. Any answer you give to this question (or any other) subsumes existence, consciousness and identity. So the only answer is "I exist, I know that I do, and all things are what they are, so I am what I am."