which one is correct?
Fridays boundless national audience had begun to gather six minutes after Lee Oswald ceased firing. At 12:36 CST Don Gardiner of the ABC radio network cut into local programs with a relay of the embattled Merriman Smith's first precede, torn off teletype machines two minutes before. At 12:40—when Kellerman was telling Behn "Look at your clock"— CBS interrupted "As the World Turns," a soapland daydream. Viewers beheld Walter Cronkite announcing that "In Dallas, Texas, three shots were fired at President Kennedy's motorcade. The first reports say that the President was 'seriously wounded.'" At 12:45 NBC, the champion of news coverage, became the last of the three to reach the public. ]
does "became the last of the three" mean there are 3 media, NBC is one of them(other two, CBS&ABC) , or does it mean" NBC is the only one last "?