Which organization conducted hearings into alleged communist activity in the government and the media during the 1950's ?

The House Un-American Activities Committee (HUAC) was created in 1938 to investigate alleged disloyalty and subversive activities on the part of those having Communist ties. It was a committee of the U.S. House of Representatives, investigated allegations of communist activity in the U.S. during the early years of the Cold War

the structure was most likely used for;

c. playing a ball game with stone hoops