The correct answer to the question is option 2, Vijayalakshmi Pandit. She served as India`s first Ambassador to the Soviet Union.

Option 1, V.P. Krishna Menon, is incorrect. While he was a prominent Indian diplomat and politician, he did not serve as India`s first Ambassador to the Soviet Union.

Option 3, KM. Pannikar, is also incorrect. Although Pannikar was an Indian diplomat and served in various diplomatic roles, he did not serve as India`s first Ambassador to the Soviet Union.

Option 4, K.R. Narayanan, is incorrect. While Narayanan was an Indian diplomat and later became the President of India, he did not serve as India`s first Ambassador to the Soviet Union.

Therefore, the only correct option is option 2, Vijayalakshmi Pandit. She played a significant role in establishing diplomatic relations between India and the Soviet Union and served as the first Ambassador to the Soviet Union.