What movie is known for reflecting gritty melodramas that question social issues during the 50s?

The film known for reflecting gritty melodramas that question social issues during the 1950s is "Blackboard Jungle." This film, released in 1955, addresses significant social issues of the time, such as juvenile delinquency, racism, and the challenges faced in the American education system. "Blackboard Jungle" is often cited as one of the first films to tackle the complexities of youth culture and the struggles of both students and teachers within an inner-city environment.

The film’s raw portrayal of life in a troubled high school and its emphasis on the impact of societal problems on education aligns it closely with the gritty melodrama genre. It stood out during a decade when American cinema began to confront more serious and relevant social issues, marking a departure from lighter, more escapist entertainment.

The other films mentioned, while significant in their own right, do not focus primarily on the kinds of social issues represented in "Blackboard Jungle." For instance, "Beach Party Bingo" primarily exemplifies the lighthearted beach party genre of the era, while "Rear Window" and "Vertigo" are both psychological thrillers that delve more into personal obsessions and perceptions rather than addressing broader societal concerns.