Given the task definition and input, reply with output. 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.

Question: Who was the mayor of Buenos Aires the year La balsa was released? Passage:"La balsa" (; Spanish for "the raft") is the debut single by the Argentine band Los Gatos, released on July 3, 1967 on Vik, a subsidiary of RCA Victor. Formed in 1967 after the disbandment of Los Gatos Salvajes, Los Gatos were the house band of the bar La Cueva, which became a popular meeting place for rock enthusiasts and the birthplace of Argentine rockknown locally as rock nacional (Spanish for "national rock"). During the mid-to-late 1960s, Buenos Aires was experiencing a cultural blossoming characterized by innovations in modern art, literature and cinema, largely driven by a burgeoning youth subculture that adhered to the countercultural phenomenon of the decade. The underground had its center in La Cueva, Plaza Francia and the Torcuato di Tella Institute, and identified with British Invasion music and the sexual revolution. "La balsa" was written by Litto Nebbialead vocalist of the bandand Tanguito (credited as Ramses) on May 2, 1967, in the men's toilet of La Perla de Once, another bar frequented by the group. At the time, Argentina was under a military dictatorship led by Juan Carlos Ongania, which regularly imprisoned and persecuted these young bohemians.
a