Concept:The title “as-Siddiq” means “the truthful” and is a well-known honorific in Islamic history.Explanation:Abu Bakr b. Abi Quhhafah was given the title “as-Siddiq” because he truthfully confirmed the Prophet’s night journey and consistently believed in his messages.The other companions listed — Abdallah b. Umar, Uthman b. Affan, and Ali b. Talib — are not known by this particular title.Answer:C. Abu Bakr b. Abi Quhhafah