Final answer:
The development of radio in the early 20th century made it a viable career option, with various types of programming and the involvement of large corporations.
Step-by-step explanation:
The development of radio in the early 20th century made it a viable career option. Initially, radio was mainly used for news broadcasting, but it quickly expanded to include various types of programming such as comedy, talk shows, educational programs, and game shows. As the popularity of radio grew, large corporations like NBC and CBS dominated the industry, creating opportunities for careers in radio.