Question: Cynthia May Carver, known professionally as Cousin Emmy, was a banjo player and country singer who was one of the pioneering solo female stars in the country music industry, her song "Ruby, Are You Mad at Your Man?", became a bluegrass standard after it was covered by the Osborne Brothers, were an influential and popular bluegrass act. during which time period?
Sentence (from "Cousin Emmy"): became a bluegrass standard after it was covered by the Osborne Brothers.
Relevant evidence: Yes