Pakistan gained independence in August 1947, and its journey in international sports began almost immediately. The first Olympic Games after its independence were the 1948 Summer Olympics held in London. Pakistan made its Olympic debut at these games, sending a contingent of athletes to represent the newly formed nation. Among the teams that participated, the Pakistan hockey team was notably present, marking its first appearance on the global Olympic stage.
Therefore, 1948 is the correct answer. The other years mentioned represent significant milestones for Pakistan in Olympic hockey, but not their debut. In 1956, Pakistan won its first Olympic medal, a silver in hockey, at the Melbourne Games. In 1960, Pakistan achieved its first Olympic gold medal, triumphing in hockey at the Rome Olympics. By 1964, Pakistan secured another silver medal in hockey at the Tokyo Games. These were all subsequent participations, not the initial one.