What was the first cartoon series created specifically for television?

The first cartoon series specifically created for television was "Crusader Rabbit." This series, which debuted in 1949, was groundbreaking as it marked the transition of animation from traditional theatrical shorts to serialized television content. Unlike other options listed, "Crusader Rabbit" was designed to appeal to a television audience from the outset, presenting short episodes that could easily fit the format of television programming at the time. Its production utilized a limited animation style that was both cost-effective and suitable for the constraints of early TV broadcasting, paving the way for future animated series aimed at children and families.

In contrast, the other titles listed either originated in different media or were developed later: "The Flintstones" debuted in 1960, while "Superman" and "Rocky and Bullwinkle" emerged during the 1950s, but neither had the focus and intent for television entertainment that "Crusader Rabbit" established.