The correct answer is option 'A', the Delimitation Commission.

The Delimitation Commission is responsible for determining the area of a Lok Sabha constituency for the purpose of general elections in India. Let's understand this in detail:

1. What is the Delimitation Commission?
The Delimitation Commission is a constitutional body established under Article 82 of the Constitution of India. It is responsible for the delimitation or division of constituencies for the purpose of elections to the Lok Sabha (the lower house of Parliament) and the State Legislative Assemblies.

2. Purpose of Delimitation:
The primary objective of delimitation is to ensure the equitable distribution of seats and to provide adequate representation to all sections of society. It aims to ensure that every constituency has a similar number of voters, thereby ensuring fairness and avoiding malapportionment.

3. Composition of the Delimitation Commission:
The Delimitation Commission is usually constituted by the President of India. It consists of a retired judge of the Supreme Court of India or the Chief Justice of a High Court as the Chairperson, and two other members who are either judges of High Courts or individuals qualified to be appointed as judges. The Election Commission of India provides necessary assistance to the Delimitation Commission.

4. Process of Delimitation:
The Delimitation Commission carries out the process of delimitation in a systematic manner. It takes into account various factors such as population density, geographical features, and administrative convenience while determining the boundaries of the constituencies. The process involves the identification of existing constituencies, the determination of the number of seats allocated to each state or union territory, and the demarcation of boundaries accordingly.

5. Role of the Election Commission of India:
While the Delimitation Commission is responsible for determining the area of a Lok Sabha constituency, the Election Commission of India is responsible for the conduct of elections and the implementation of the delimitation exercise. The Election Commission ensures that the delimitation process is carried out effectively and that the elections are conducted smoothly.

In conclusion, the area of a Lok Sabha constituency for the purpose of general elections is determined by the Delimitation Commission. This constitutional body plays a crucial role in ensuring fair representation and equitable distribution of seats in the Lok Sabha.