Q: Context: The "Super Mario Bros. theme", officially known as the "Ground Theme" ( BGM, Chijo BGM, lit. "Aboveground BGM") or Overworld Theme, is a musical theme originally heard in the first stage of the 1985 Nintendo Entertainment System video game Super Mario Bros ... It was one of six themes composed for the game by Nintendo sound designer Koji Kondo, who found it to be the most difficult track to compose for it. The theme has a calypso rhythm and usually receives a corresponding orchestration in games whose sound synthesizers can imitate steel drums.

Question: who made the super mario bros theme song? Let's give stream of consciousness first:
The relevant sentence in the passage is: It was one of six themes composed for the game by Nintendo sound designer Koji Kondo, who found it to be the most difficult track to compose for it. Therefore, the final answer is Nintendo sound designer Koji Kondo.