Step 1: Understanding Kant's Postulates of Morality.
Immanuel Kant's moral philosophy posits that for morality to be meaningful, certain assumptions are necessary: - C. Freedom of Will: Kant asserts that moral accountability hinges on the assumption that individuals possess the autonomy to act in accordance with their rational decisions. - D. Existence of God: Kant considered the existence of God a requisite postulate, as it guarantees ultimate justice and coherence within the moral framework. - A. Mortality of Soul and B. Immortality of Soul are not directly pertinent to Kant's postulates of morality.
Step 2: Conclusion. The correct selection is 2, encompassing only C and D.
Final Answer: \[ \boxed{\text{The correct answer is 2. C and D only.}} \]