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 long was Ebrahimzadeh coach at Naft Tehran? Passage:He was selected as Sepahan's assistant coach in 2006 by Luka Bonačić. After Sepahan was unable to win the 2007–08 season and was ranked as runner up like AFC Champions League and winning Hazfi Cup in both 2006 and 2007, Bonačić was resigned as Sepahan's head coach and was appointed as Dubai based team, Al-Nasr Sports Club. He was selected Ghanbari as his first team assistant coach which was worked with him until his dismissal in February 2009. After he expired his contract with Al-Nasr, he became assistant manager of Sepahan for a second time under management of Amir Ghalenoei. He continue his career with Sepahan after Ghalenoie's resignation in 2011. Bonačić was appointed as Sepahan head coach for a second tensure and Ghanbari was one of his assistants. On 14 August 2011 and after Bonačić was sacked by club due to bad results, Ghanbari became caretaker manager of Sepahan. He was replaced with Zlatko Kranjčar after Sepahan was eliminated from Hazfi Cup. On 30 May 2012, he was named as Mansour Ebrahimzadeh's assistant coach in Naft Tehran. After Ebrahimzadeh signed as head coach of Rah Ahan, Ghanbari also signs a contract to become his assistant.


b