Which autonomous constitutional body of India has its headquarters in the building known as Nirvachan Sadan in New Delhi?

Introduction / Context:
Many exam questions test familiarity with the locations of important national institutions. Nirvachan Sadan, located on Ashoka Road in New Delhi, is a key landmark connected with the conduct of elections in India. Knowing which body functions from this building helps you link constitutional institutions to their physical headquarters, which is a common pattern in general knowledge questions.

Given Data / Assumptions:
• The building name given is Nirvachan Sadan. • It is located in New Delhi on Ashoka Road. • The options list several national level bodies and institutions. • The question asks which autonomous body is headquartered there.

Concept / Approach:
The word Nirvachan in Hindi relates to elections. Nirvachan Sadan is therefore literally the House of Elections. It serves as the headquarters of the Election Commission of India, which is the constitutional body responsible for administering elections to the Lok Sabha, Rajya Sabha, State Legislative Assemblies, and the offices of President and Vice President. Other bodies listed in the options have their own separate premises and are not associated with Nirvachan Sadan. Recognising the meaning of the name and recalling standard facts about institutional headquarters leads directly to the correct answer.

Step-by-Step Solution:
Step 1: Translate or understand the word Nirvachan as election, which hints at an electoral institution. Step 2: Recall that the Election Commission of India is a constitutional body that oversees elections across the country. Step 3: Match this with the knowledge that its head office is at Nirvachan Sadan on Ashoka Road in New Delhi. Step 4: Examine the options and identify the Election Commission of India as the only body directly related to elections. Step 5: Choose Election Commission of India as the correct option.

Verification / Alternative check:
Official contact pages and government directories list the Election Commission of India with its address at Nirvachan Sadan, Ashoka Road, New Delhi. They clearly label this building as the commission's headquarters, where the Chief Election Commissioner and other Election Commissioners sit. No similar references connect Nirvachan Sadan to the Union Public Service Commission, the Central Bureau of Investigation, AIIMS, or the Comptroller and Auditor General of India, which confirms that this building belongs to the Election Commission of India.

Why Other Options Are Wrong:
• The Union Public Service Commission is headquartered at Dholpur House on Shahjahan Road, not at Nirvachan Sadan. • The Central Bureau of Investigation functions under the Ministry of Personnel and has separate office complexes, not this building. • The All India Institute of Medical Sciences is a premier medical institute and hospital in New Delhi, but its campus is known by its institutional name, not as Nirvachan Sadan. • The Comptroller and Auditor General of India has separate offices and is not linked with the name Nirvachan Sadan.

Common Pitfalls:
• Confusing the UPSC with the Election Commission because both are constitutional bodies involved in selection processes. • Ignoring the linguistic clue in the building name, which clearly relates to elections. • Guessing based only on institutional prominence without recalling the specific headquarters location.

Final Answer:
Nirvachan Sadan in New Delhi is the headquarters of the Election Commission of India.