听力原文： A leading Senate Democrat says the US detention center at Guantanamo Bay, Cuba, should be shut down. Senator Joe Biden added his voice to the reaction to a Pentagon report released Friday. The report details five incidents in which US guards and interrogators desecrated the Koran at Guantanamo Bay, Cuba. Speaking on ABC Biden says he thinks the US should move towards closing Guantanamo. "We should end up shutting it down, moving those prisoners. Those we have reason to keep, keep. Those we don't, let go."
The topic also came up on CNN. Democrat K said he didn't believe that it was necessary to close down Guantanamo, and Republican Senator Mitch McConnell seethes over Amnesty International's use of the word "gulag" to describe the prison. He said it's difficult to run a perfect prison.
______ supports to shut down Guantanamo Bay prison？

A. Democrat K
B. Pentagon
Cuba
Democrat senator Joe Biden