Concept:
The 91st Constitutional Amendment Act, 2003, was enacted to curb the practice of excessively large ministries and promote efficiency and fiscal discipline in governance.
Step 1: Identify the constitutional provision.
The amendment inserted Article 75(1A), which prescribes a maximum size for the Union Council of Ministers.
Step 2: Understand the limit.
Article 75(1A) provides that the total number of ministers, including the Prime Minister, shall not exceed 15% of the total strength of the Lok Sabha.
Step 3: Note the corresponding state provision.
Article 164(1A) similarly limits the size of the State Council of Ministers to 15% of the strength of the Legislative Assembly, subject to a minimum of 12 ministers.
Therefore, Option (D) is correct.