Definition: In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: How many years had Ernest Lawrence worked at UCLA before Backus attended? Passage:John Backus was born and raised in Portland, Oregon, where he studied at Reed College, receiving a BA in 1932. He went on to graduate studies at the University of California, Berkeley, where he did research in nuclear physics at the Radiation Laboratory under Ernest Lawrence. He received an MA in 1936, and a PhD in 1940. In 1945 he was appointed Professor of Physics at the University of Southern California, a post he retained until his retirement in 1980. During the early part of his career, his research focussed on gaseous discharges in strong magnetic fields. He was also a musician, trained as a performer on piano, bassoon, clarinet and other woodwinds and received the degree of MMus in conducting from the University of Southern California in 1959. In his later career he turned increasingly to the study of musical acoustics, particularly those of wind instruments and organ pipes. In 1969 he published The Acoustical Foundations of Music, a book which became a standard text for introductory courses in musical acoustics. A second edition appeared in 1977. He received the Silver Medal of the Acoustical Society of America in 1986. Backus died in Los Angeles in 1988.


b