Answer:
(C) A shrinking population in the East drove Americans to live in cities
Step-by-step explanation:
There were several reason for expanding towards the west, lots of land available in the west and the good soil could be used for farming. Califronia gold rush also contributed to the westward expansion. The expansion was made easy due to advancement in the transportation such as Canals, Steamboats and overland trails and idea of manifest destiny motivated people to move toward west considering it as a patriotic responsibility. All the other factors are correct except (C) A shrinking population in the East drove Americans to live in cities was not a reason for westward migration.