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: How long did the war that Potter fought in as an officer in the Royal Field Artillery last? Passage:Potter was born in Bedford to Reverend Brignal Peel, a Wesleyan minister, and Elizabeth Stimson. He was educated at Bedford Modern School and for a time at Worcester College, Oxford. He first performed in E. M. Royle's The White Man at the Lyric Theatre in London before touring. In 1915 he was George Robey's understudy at the Alhambra. During the Great War Potter served as a 2nd lieutenant in the Royal Field Artillery in France. He served in the 6th Division 2nd Brigade 21st Battery, from 8 February 1917 before returning to music hall once the war was over. Potter cultivated an individual style and persona, wearing a straw boater, wide grey flannel trousers (he said he invented the Oxford bags style at the Coliseum in 1920), an 'Old Borstolian' blazer and carrying a notebook with a rolled umbrella. James Agate described him as "that sham Harrovian who bears upon his blazer the broad arrows of a blameful life".
 Links: a. Harrow School b. World War I c. Lyric Theatre, London d. World War I
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 Nüsslein-Volhard b. Lewis Wolpert c. Lewis Wolpert d. Transcription factor
Example Output: a

Example Input: Question: Who directed the movies that Harikrishna was in during 1974? Passage:Harikrishna made his acting debut in 1964 as a child artist in Sri Krishnavataram, in which he played Krishna. It was directed by Kamalakara Kameshwara Rao. He then starred in Thalla? Pellama? (1970), which was followed by Tatamma Kala (1974), Ram Raheem (1974) and Daana Veera Shura Karna (1977). After long years of sabbatical, and political stint he then started as a Character actor in works such as Sri Ramulayya (1998), followed by a full length role alongside Nagarjuna in Seetharama Raju (1999), Lahiri Lahiri Lahirilo (2002) and Seetayya (2003). In 2002, he received Nandi Award for Best Character Actor for his work in Lahiri Lahiri Lahirilo. Harikrishna died in a crash on 29 August 2018 at age 61. He served as the member of Andhra Pradesh Legislative Assembly during 1996-1999. He became a Cabinet Minister for Road Transport in 1996. In 2008, he was a candidate of the Telugu Desam Party and was elected to Rajya Sabha.
 Links: a. Lahiri Lahiri Lahirilo b. Lahiri Lahiri Lahirilo c. Sri Krishnavataram d. Tatamma Kala
Example Output:
d