Given the task definition and input, reply with output. 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: Which of the three famous classical and opera venues in San Francisco is the oldest? Passage:Classical and Opera venues in San Francisco include the San Francisco Symphony, the San Francisco Opera and the San Francisco Ballet. They all perform at the San Francisco War Memorial and Performing Arts Center. San Francisco's Ballet and Opera are some of the oldest continuing performing arts companies in the United States. San Francisco is the birthplace and home city of the vocal ensemble Chanticleer. The city is also home to the American Conservatory Theater, also known as A.C.T., which has been routinely staging original productions since its arrival in San Francisco in 1967. Additionally, the New Conservatory Theatre Center (NCTC) is known for being an intimate theater that routinely stages original productions by the local, national, and international LGBT community. Hundreds of smaller, alternative theatres also attract a significant portion of the audience given their historical role in the San Francisco performing arts culture. The oldest of these are Intersection for the Arts, founded in 1965, and the Magic Theatre, founded in 1967. A major player in the promotion of theater in the Bay Area is Theatre Bay Area (or TBA). A non profit organization, Theatre Bay Area has members from more than 365 Bay Area theatre and dance companies, is the publisher of Callboard Magazine, and runs San Francisco's Half-Priced Ticket Booth.
Links: a. Theatre Bay Area b. San Francisco Symphony c. San Francisco Symphony d. Magic Theatre
b