You are standing in front of ten people, one of which is a truth-teller while the other nine are togglers . (A toggler is a person who toggles between the-truth and the-lie for every question asked.) You have no clue who the truth-teller is and who the togglers are.
You are given the chance to ask one and only one question to any, but only one of the ten people. From the provided answer you must be able to deduce with certainty the identity of the truth teller.
Question: So what is that question you will be asking?