Which of the following actions is most similar to city-planning techniques developed by the aztecs?
a. a business relocates its headquarters outside a big city to avoid paying the city's high taxes.
b. a city opens a new elementary school to serve a large immigrant population living on its outskirts.
c. a university designs a new building to ensure that astronomers will be able to easily observe the night sky.
d. a police force opens new police stations in neighborhoods that have had consistently high crime rates.