Which one of the following statements in respect of the States of India is not correct?

The statement in option D is incorrect because the size of the Council of Ministers in Delhi is governed by Article 239AA of the Constitution.

• Delhi's Limit: According to Article 239AA(4), the Council of Ministers shall not exceed 10 percent of the total number of members in the Legislative Assembly. For Delhi's 70-member assembly, this means a maximum of 7 ministers.
• Other States: The 15 percent limit applies to the Union Council of Ministers and other State Councils of Ministers under the 91st Constitutional Amendment Act, 2003.
• Other Options: In 2018, Jammu and Kashmir legally held its own Constitution (Statement B is correct). Statement C is correct as the Indian Union is permanent and states cannot secede. Statement A reflects the general rule of a single constitution for the entire country.