Which of the following factors is not responsible for growth in the urban population?

None of the above

The correct answer is Option 4: None of the above

Option (1): Reclassification of urban areas to encompass formerly rural population settlements. — This statement is correct. When rural settlements are reclassified as urban areas, the urban population increases.

Option (2): Net in-migration — This statement is correct. Migration of people from rural areas to towns and cities contributes to urban population growth.

Option (3): Natural increase — This statement is correct. Increase in births over deaths in urban areas also raises the urban population.

Since all the above factors contribute to urban population growth, none of them is incorrect.

NCERT: Urban population grows as a result of natural increase (when birth rate exceeds death rate), net in-migration (when people move in than out), and sometimes reclassification of urban areas to encompass formerly rural population settlements.