Question: Of which river is the body of water, that marks the change from Grand Street to Grand Avenue, a tributary ?
Sentence (from "Myrtle Avenue (BMT Lexington Avenue Line)"): It closed on October 13, 1950, although the other BMT station at that location, Grand Avenue was in operation until January 21, 1953, while the rest of the line southwest of Broadway was operational until November 3, 1969.
Relevant evidence: No