Option (D) is correct because the textbook clearly states that 'normally, in the parliamentary system, a leader who has the support of the majority in the Lok Sabha would be appointed as Prime Minister.' This means the President appoints the leader who commands majority support in the Lok Sabha, whether from a single party or an alliance. Option (A) is incorrect because the largest party may not necessarily have a majority. Option (B) is partially correct but too specific—it limits the choice to the 'largest party in the alliance,' whereas the leader could be from any party within the alliance. Option (C) is wrong because the Prime Minister must have support in the Lok Sabha, not the Rajya Sabha.