Answer:
A. the mythic ideas of what the city was built on.
Step-by-step explanation:
In the text, Athena and Poseidon'd Contest for Athens, the speaker talks about how the gods Athena and Poseidon were in a contest for the possession of the city of Athens. The story of how Athena came to be the "patron deity of Athens" reveals how the modern-day Athens came to be.
Paragraph 1 of the text describes how major gods were the basis of how the modern-day cities were established. Though ancient in their legends, they are nonetheless "often conscripted into worthy causes, such as the creation of a new town; laying the metaphoric foundations for what was to prosper into our contemporary major cities that we still walk in today". The use of the word "metaphoric foundations" reveals how these mythic ideas became the basis of what a city was built on.
Thus, the correct answer is option A.