What is the definition of multicasting in the context of OTA broadcasting of DTV content?

Multicasting in the context of over-the-air (OTA) broadcasting of digital television (DTV) content refers specifically to the ability to transmit multiple streams of content over a single channel simultaneously. Option B is correct because it highlights the transmission of a single high-definition service while also delivering one or two standard definition services. This reflects how multicasting allows broadcasters to optimize the use of their available bandwidth to provide viewers with a variety of options on the same channel.

This concept is crucial in modern broadcasting since it enables stations to offer diverse programming without requiring additional spectrum, thus enhancing the viewing experience through more choices. Multicasting also often allows for prioritizing a high-definition main channel while still providing standard definition options for viewers who may have different reception capabilities or device preferences.