Concept:Surah Al-Ikhlas is the chapter of the Qur'an that most directly emphasises the oneness of Allah, known as Tawhid.Explanation:Monotheism means the belief in the absolute oneness of Allah.Surah Al-Ikhlas begins with the declaration "Say: He is Allah, the One" and continues to stress His uniqueness, self-sufficiency, and incomparability.This surah is often described as the essence of Tawhid, making the theme of monotheism its central message.The other listed surahs do not focus as directly or exclusively on this theme.Answer:B. al-Ikhlas