Why do people called Queen Elizabeth I is The Queen Mother? (sorry for my bad english.)

(any confusion, tell me.)

A. Because she is a mother.

B. Because she is queen.

C. To avoid confusion with her
daughter.

D. To know she had two kids.

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.