Final answer:
Option D provides the best support for the statement that some artwork from the period encouraged westward migration, as Bierstadt's paintings showcased the U.S. natural resources favorably.
Therefore, option D is correct.
Step-by-step explanation:
The statement that some artwork from this period tried to persuade people to move out West is best supported by option D: Bierstadt's massive paintings confirmed that the U.S. possessed beautiful natural resources comparable to those in Europe. This sentence highlights the role of art in depicting the American West as a land of opportunity and natural beauty, which would have been compelling to those considering migration. Artists like Albert Bierstadt and Thomas Moran used their artwork to inspire and educate people about the West, contributing to the national parks movement and the wider desire to reserve wilderness areas. Such works celebrated the American landscape and contributed to the romanticization of westward expansion, in line with the ethos of Manifest Destiny.