According to Paul's letter to the Galatians, what was the primary purpose of the Law (Torah) before the coming of Christ?

A To provide a perfect standard of righteousness achievable through human effort. B To reveal the holiness of God and the sinfulness of humanity, serving as a 'guardian' or 'disciplinarian'. C To establish a distinct national identity for the Jewish people, separate from the Gentiles. D To offer a temporary system of atonement for sins until a more permanent sacrifice could be made.