What caused the Spartans to halt their siege of Athens? a. threat of Persian naval intervention on Athens' side
b. a plague that broke out in the villages of Athens
c. The Athenian army landed on the Peloponnesian Peninsula.
d. Delian league money used by Athens to pay Sparta to end its siege

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.