In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Example Input: Question: Did Vordtriede's family join him in America beside his mother? Passage:After the Nazis came to power, he emigrated to Switzerland in 1933 and to the United States later. He began his studies in Zurich and worked part-time as a house teacher. Meanwhile, he wrote articles and book reviews for the Neue Zurcher Zeitung, using several pseudonyms because of prohibition of work. He earned his PhD and taught French and German Literature at various universities, including Princeton University and University of Wisconsin-Madison. During a journey to Europe, Vordtriede was surprised by the outbreak of the Second World War and interned as an Enemy alien in occupied France. By interventions, he became free months later and was allowed to go back to America. He met his mother in New York City late in 1941, who also emigrated to the USA. He received the American citizenship in 1946 and became a Guggenheim Fellow in 1957. His sister Franze emigrated in 1947 and went to Philadelphia.
Links: a. University of WisconsinMadison b. Philadelphia c. University of WisconsinMadison d. Switzerland
Example Output: b

Example Input: Question: How old was Nusslein-Volhard when she won the Nobel Prize in Physiology and Medicine? Passage:The concept of the morphogen has a long history in developmental biology, dating back to the work of the pioneering Drosophila (fruit fly) geneticist, Thomas Hunt Morgan, in the early 20th century. Lewis Wolpert refined the morphogen concept in the 1960s with the French flag model, which described how a morphogen could subdivide a tissue into domains of different target gene expression (corresponding to the colours of the French flag). This model was championed by the leading Drosophila biologist, Peter Lawrence. Christiane Nusslein-Volhard was the first to identify a morphogen, Bicoid, one of the transcription factors present in a gradient in the Drosophila syncitial embryo. She was awarded the 1995 Nobel Prize in Physiology and Medicine for her work explaining the morphogenic embryology of the common fruit fly. Groups led by Gary Struhl and Stephen Cohen then demonstrated that a secreted signalling protein, Decapentaplegic (the Drosophila homologue of transforming growth factor beta), acted as a morphogen during the later stages of Drosophila development.
Links: a. Christiane Nusslein-Volhard b. Lewis Wolpert c. Lewis Wolpert d. Transcription factor
Example Output: a

Example Input: Question: When did the sultan who installed Baba begin his rule? Passage:Somuncu Baba is one of the virtuous men who came to Anadolu for spiritual conquest, he was also a descendant of Islamic prophet Muhammad After receiving an education in cities which are the center of knowledge like Sam, Tabriz, Erdebil, he settled in Bursa for his guidance and duty. He taught at the Bursa Grand Mosque where he was installed by Sultan Bayezid I after it was completed. For hiding his spiritual side, he baked bread and sold them so he was known as Somuncu Baba. He became known after he had translated the sura of Al-Fatiha, in seven different ways during the opening of Bursa Grand Mosque, in Bursa. He avoided becoming famous so he left Bursa and moved Aksaray. He left his son Yusuf Hakiki Baba in Aksaray and he went to Mecca with his son Halil Taybi when they got back to Anadolu they settled in Darende and he died here in 1412. His tomb is still in Darende.
Links: a. Bayezid I b. Damascus c. Darende d. Anatolia
Example Output:
a