Hulu LLC said on Wednesday it has launched its live TV streaming service, putting itself in the center of a growing and competitive market as viewers increasingly watch TV through the internet rather than on cable and satellite television. For $40 a month, Hulu will offer 50 sports, news, entertainment and kids’ channels, including ABC, CBS, FOX and NBC, CNN, CNBC, Fox News, MSNBC, A&E and the Disney Channel.