Explanation:

Citizenship is listed in the Union List under the Constitution and thus is under the exclusive jurisdiction of Parliament.

• The Constitution does not define the term ‘citizen’ but details of various categories of persons who are entitled to citizenship are given in Part 2 (Articles 5 to 11).
• The Citizenship Act of 1955 prescribes five ways of acquiring citizenship, viz, birth, descent, registration, naturalisation and incorporation of territory.
• Article 6 of the Indian Constitution provides the rights of citizenship of certain persons who have migrated to India from Pakistan. 

The Government of India may terminate the citizenship of an Indian citizen if;

• The citizen has disrespected the Constitution.
• Has obtained citizenship by fraud.
• The citizen has unlawfully traded or communicated with the enemy during a war.
• Within 5 years of registration or naturalisation, a citizen has been sentenced to 2 years of imprisonment in any country.
• The citizen has been living outside India for 7 years continuously.

Hence only statement 2nd is correct.