Which one of the following is not one of the modes of acquisition of c

Which one of the following is not one of the modes of acquisition of citizenship under the Citizenship Act, 1955 ?

Descent
Registration
Incorporation of territory
Overseas citizenship/dual citizenship
This question was previously asked in
UPSC CISF-AC-EXE – 2017
The Citizenship Act, 1955, provides for the acquisition of Indian citizenship by five ways: by Birth, by Descent, by Registration, by Naturalisation, and by Incorporation of territory. Overseas citizenship/dual citizenship is not a mode of *acquiring* Indian citizenship under this Act. Overseas Citizenship of India (OCI) is a status granted to persons of Indian origin who are citizens of another country; it is not equivalent to Indian citizenship, and India generally does not allow dual citizenship as per its constitution and laws.
– Indian citizenship can be acquired after the commencement of the Constitution (Jan 26, 1950) through the mechanisms specified in the Citizenship Act, 1955.
– The Constitution (Part II, Articles 5 to 11) deals with citizenship at the commencement of the Constitution and grants Parliament the power to regulate the right of citizenship.
– Overseas Citizen of India (OCI) status was introduced in 2005. OCI cardholders are granted multiple entry lifelong visas, exemption from reporting to the police for any length of stay in India, and parity with NRIs in financial, economic and educational fields, but they do not have political rights (like voting or holding public office).