Along with Russell Simmons, the producer of the Avett Brothers album "Magpie and the Dandelion" co-founded what record label? 
Magpie and the Dandelion:  The album was produced by Rick Rubin who produced their previous two full-length studio albums, 2009's "I and Love and You" and 2012's "The Carpenter". Rick Rubin:  Along with Russell Simmons, Rubin is the co-founder of Def Jam Records and also established American Recordings.
Def Jam Records