Given the task definition and input, reply with output. Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.

proper question: What encouraged trade under the Yuan?
disfluent question: What encouraged drama or uh trade under the Yuan?
context: A rich cultural diversity developed during the Yuan dynasty. The major cultural achievements were the development of drama and the novel and the increased use of the written vernacular. The political unity of China and much of central Asia promoted trade between East and West. The Mongols' extensive West Asian and European contacts produced a fair amount of cultural exchange. The other cultures and peoples in the Mongol World Empire also very much influenced China. It had significantly eased trade and commerce across Asia until its decline; the communications between Yuan dynasty and its ally and subordinate in Persia, the Ilkhanate, encouraged this development. Buddhism had a great influence in the Yuan government, and the Tibetan-rite Tantric Buddhism had significantly influenced China during this period. The Muslims of the Yuan dynasty introduced Middle Eastern cartography, astronomy, medicine, clothing, and diet in East Asia. Eastern crops such as carrots, turnips, new varieties of lemons, eggplants, and melons, high-quality granulated sugar, and cotton were all either introduced or successfully popularized during the Yuan dynasty.
The political unity of China and much of central Asia