Read the excerpt from President Ronald Reagan’s Address at Moscow State University.

But progress is not foreordained. The key is freedom—freedom of thought, freedom of information, freedom of communication. The renowned scientist, scholar, and founding father of this university, Mikhail Lomonosov, knew that. "It is common knowledge," he said, "that the achievements of science are considerable and rapid, particularly once the yoke of slavery is cast off and replaced by the freedom of philosophy." You know, one of the first contacts between your country and mine took place between Russian and American explorers. The Americans were members of Cook's last voyage on an expedition searching for an Arctic passage; on the island of Unalaska, they came upon the Russians, who took them in, and together with the native inhabitants, held a prayer service on the ice.

In this excerpt, President Reagan expresses his opinion that the key to progress is freedom. This is

a substantiated opinion because Reagan quotes an expert.
a substantiated opinion because Reagan lists many freedoms.
an unsubstantiated opinion because Reagan shares personal feelings.
an unsubstantiated opinion because Reagan gives a historical example.