What was the real name of Swami Vivekananda, the famous Indian monk and spiritual leader who represented India at the Parliament of the World Religions in Chicago in 1893?

Introduction / Context:
This question belongs to Indian culture and modern history. Swami Vivekananda is one of the most respected spiritual leaders from India, known worldwide for his speech at the 1893 Parliament of the World Religions. Many saints and leaders received new names after joining monastic orders, so exams often ask about their original names.

Given Data / Assumptions:
- The figure in question is Swami Vivekananda.
- The question asks for his real or birth name before he became a monk.
- The options list several Bengali sounding names, only one of which is correct.
- We assume basic familiarity with teachings and life story of Swami Vivekananda as part of Indian cultural studies.

Concept / Approach:
Swami Vivekananda was born in a Bengali family in Kolkata. His birth name was Narendranath Datta, sometimes written as Dutta or Datt in transliteration. When he became a disciple of Sri Ramakrishna and later took monastic vows, he adopted the name Swami Vivekananda. Recognising this link between his monastic name and his given name is the key to answering the question.

Step-by-Step Solution:
Step 1: Recall basic biography. Swami Vivekananda was born as Narendranath Datta in 1863. Step 2: Connect that he studied in Kolkata, was influenced by Sri Ramakrishna, and later became a monk. Step 3: Observe the options and notice that Narendranath Datta appears exactly as a choice. Step 4: Confirm that none of the other names match the commonly known birth name of Swami Vivekananda. Step 5: Conclude that Narendranath Datta is the correct answer.

Verification / Alternative Check:
Another check is to remember that many books and institutions associated with him use the name Narendranath in early chapters or sections when describing his childhood. Biographical films, school textbooks, and the Ramakrishna Mission literature all consistently refer to Swami Vivekananda childhood name as Narendranath Datta. The spelling with double t or single t at the end can vary in English, but the pronunciation and identity remain the same.

Why Other Options Are Wrong:
Surendranath Bose is a different name and does not match Vivekananda biography.
Vidyadhar Roy, Shyamal Bose, and Debendranath Sen are not historically associated as the birth name of Swami Vivekananda and appear here only as distractors.
None of these names appear in standard biographies of Swami Vivekananda.

Common Pitfalls:
Sometimes candidates confuse Narendranath Datta with other leaders whose names also end with nath. Another mistake is to misread the spelling and discard the correct option because of minor variations like Datta or Dutta. The key is to recognise the core name Narendranath, which clearly identifies the young Vivekananda before he took monastic vows.

Final Answer:
The real name of Swami Vivekananda was Narendranath Datta.