You will be given a definition of a task first, then some input of the task.
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.

Question: In which country was Laudal a research fellow? Passage:He was born in Kirkenes as the son of teachers Trygve Laudal (18961964) and Agnes Mnnesland (18981982). He finished his secondary education in 1954 in Mandal, and enrolled in the University of Oslo in the same year. He studied at Ecole Normale Superieure from 1957, but in 1958 he was back in Oslo and took the cand.real. degree. He was a research fellow at Columbia University and Institut Henri Poincare between 1959 and 1962. He was appointed as lecturer at the University of Oslo in 1962, was promoted to docent in 1964 and was a professor from 1985 to 2003. His most notable book is 1979's Formal Moduli of Algebraic Structures. He was among the founders of the Abel Prize, and has been involved in the International Centre for Theoretical Physics. He is a member of the Norwegian Academy of Science and Letters, and has been a deputy member of Brum municipal council for the Socialist Left Party.
Links: a. Examen artium b. Mandal, Norway c. Docent d. Columbia University
Output:
d