Query: Which former president of Def Jam called Beyonce the greatest entertainer alive?
Context: According to Barbara Ellen of The Guardian Beyoncé is the most in-charge female artist she's seen onstage, while Alice Jones of The Independent wrote she "takes her role as entertainer so seriously she's almost too good." The ex-President of Def Jam L.A. Reid has described Beyoncé as the greatest entertainer alive. Jim Farber of the Daily News and Stephanie Classen of Star Phoenix both praised her strong voice and her stage presence.