Consider the following in relation to causes of urbanization and select the correct answer from the code given below:
1. High rate of emigration from rural to urban areas.
2. Increasing number of educational institutions in cities.
3. High rate of industrialization.
4. High standard of living in the rural area.

1. A.1, 2 and 3 are correct
2. B.2, 3 and 4 are correct
3. C.1, 2 and 4 are correct.
4. D.1, 3 and 4 are correct.