Who appoints the Prime Minister?

Explanation:

The President has been given constitutional authority to invite the Lok Sabha Leader of the party with the most seats to form the government.

The party with the most seats must next discuss and choose a Prime Minister.

The party then establishes its majority in the Lok Sabha.

The President appoints the Prime Minister when the party has established a majority in the House.

Final answer:

Hence, the correct answer is option A, i.e., President.