Read these sentences from a concluding paragraph.

Trade thrived in Mauryan India because of good government.
Mauryan India enjoyed an era of social harmony and religious expansion.
Chandragupta Maurya's support of Jainism and Aśoka's support of Buddhism spread peace across India.
Which statement best describes the purpose of sentence 2?

It introduces new information.
It restates the essay’s thesis statement.
It reviews evidence presented to readers.
It summarizes the main ideas of the essay.