Consider the following statements :

The rate of population growth is increasing in the country

The death rate is declining faster in the country compared to birth rate

The birth rate is declining faster in the country compared to death rate

Rural-urban migration is taking place regularly in the country

Which one of the following conclusions may be true in the light of the above facts ?

The rate of population growth is increasing due to rural-urban migration

The rate of population growth is increasing due to decline in death rate only

The rate of population growth is increasing due to increase in birth rate only

The rate of population growth is increasing due to faster decline in death rate than in birth rate