Final answer:
The correct answer is option b) 80 years old.
Step-by-step explanation:
In the Old Testament book of Exodus, Moses receives a divine revelation from God on Mt. Sinai. The age of Moses when God appeared to him on Mt. Sinai is a significant detail in the religious texts of the Old Testament.
According to the biblical account, Moses was 80 years old when he led the Israelites out of Egypt and subsequently received the Ten Commandments from God on Mt. Sinai. This event is one of the pivotal moments in the book of Exodus, illustrating Moses' role as a prophet and leader.