The correct answer is D. He founded the House of Wisdom to encourage Arabic translation.
Step-by-step explanation:
Al-Ma'mun was one of the Caliphates that governed the Muslim empire whose capital was in Iraq and extended to other territories from 786 to 833 During his reigned, Al-Ma'mun was especially interested in ending with the rebellions that had emerged in the territory and strengthing education. Indeed, Al-Ma'mum was responsible for founding the House of Widom that was an academic, intellectual center and library that contain documents and materials related to the empire and a translation department in charge of Arabic translation. Additionally, this academy played an important role during the Islamic Golden Age or the period in which science and culture flourished in this Empire. Therefore, Al-Ma'mun's contribution to the Islamic Golden Age was "he founded the House of Wisdom to encourage Arabic translation".