Step 1: Understanding the Concept:
The question asks to identify the chief architect of India's foreign policy in its formative years after independence.
Step 2: Detailed Explanation:
Pt. Jawaharlal Nehru is widely regarded as the principal founder of India's foreign policy.
As India's first Prime Minister and also its first Minister of External Affairs, he held both portfolios from 1947 until his death in 1964.
He had a profound influence on shaping the core principles of India's approach to the world. Key tenets like the policy of Non-Alignment, Afro-Asian solidarity, and the Five Principles of Peaceful Coexistence (Panchsheel) were all formulated and championed by him. These principles guided India's foreign relations for decades.
While Sardar Patel had a significant role in domestic affairs, foreign policy was predominantly Nehru's domain.
Step 3: Final Answer:
Pt. Jawaharlal Nehru, as the first Prime Minister and Foreign Minister, was the main founder of Indian Foreign Policy.
Hence, option (D) is correct.