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 groups played in the Festival? Passage:In February 2009, the band toured Europe; a number of the U.K. dates were part of a package tour sponsored by Metal Hammer dubbed "Defenders of the Faith" featuring Dimmu Borgir as co-headliners. The group then toured Australia through March as part of the Soundwave Festival, which was headlined by Nine Inch Nails and Alice in Chains. In April 2009, the group began a headlining North American tour, sponsored by No Fear Energy. The leg began in Phoenix, Arizona and wrapped up mid-May in North Myrtle Beach, South Carolina. In July 2009, during a European summer tour, guitarist Mark Morton exited the tour prior to the final six dates as he and his wife were expecting their first child. Morton was replaced by Buz McGrath of Unearth for the remaining summer dates, and Doc Coyle of God Forbid for.the first three weeks of a fall North American leg. Morton eventually rejoined the group in October in Tampa, Florida.


a