Correct Option: A. Increase in death rate Explanation of the Correct Answer: To understand why an increase in the death rate would not increase the population of a country, we need to look at the basic principles of population dynamics. The population of a country is influenced by three main factors: birth rate, death rate, and migration (which includes both immigration and emigration).

1. Population Growth Formula: The basic formula for population change is: [ \text{Population Change} = \text{Births} - \text{Deaths} + \text{Net Migration} ]
2. Births contribute positively to population growth.
3. Deaths contribute negatively to population growth.
4. Net Migration is the difference between the number of people entering (immigration) and leaving (emigration) a country.
5. Increase in Death Rate:
6. When the death rate increases, it means that more people are dying within a given time period. This directly reduces the total population because the number of deaths is subtracted from the number of births.
7. For example, if a country has a birth rate of 20 births per 1,000 people and a death rate of 10 deaths per 1,000 people, the population is growing. However, if the death rate increases to 15 deaths per 1,000 people, the net growth is reduced, leading to a slower population increase or even a decline.

Explanation of the Other Options: B. Decrease in birth rate: - A decrease in the birth rate means fewer babies are being born. This would also lead to a slower population growth or a decline in population over time. Therefore, this option would not increase the population. C. Emigration: - Emigration refers to people leaving a country. When people emigrate, the population of the country decreases because they are no longer counted in the population. Thus, emigration does not contribute to population growth; it reduces it. D. Migration: - Migration can be a bit tricky because it encompasses both immigration (people coming into a country) and emigration (people leaving a country). However, if we consider migration in the context of net migration (immigration minus emigration), it can either increase or decrease the population depending on the balance. If more people immigrate than emigrate, the population increases; if more people emigrate than immigrate, the population decreases. However, the term "migration" alone does not guarantee an increase in population. Summary of Key Points:

• An increase in the death rate directly reduces the population, making option A the correct answer.
• A decrease in the birth rate and emigration both lead to a decline in population.
• Migration can either increase or decrease the population depending on the net effect of immigration and emigration.
• Understanding the dynamics of birth rates, death rates, and migration is crucial for analyzing population changes.

Revision Summary:

• Population change is determined by births, deaths, and net migration.
• An increase in the death rate decreases population size.
• A decrease in the birth rate and emigration also lead to population decline.
• Migration's effect on population depends on the balance of immigration and emigration.