Final answer:
According to Aquinas, natural law is not God's known to human reason, but a set of principles that can be discovered through human reason alone. The correct option is (2).
Step-by-step explanation:
According to the medieval philosopher Thomas Aquinas, natural law is not God's known to human reason. Instead, natural law is a set of principles that govern the natural world and can be discovered through human reason alone.
Aquinas believed that humans were given reason by God to learn about these natural laws, but divine laws, which allow humans to reach salvation, cannot be known through human reason alone and require revelation from God.