Answer:
B. An increase of 6 per 1000 people
Step-by-step explanation:
Birth rate of a population is the total live births that takes place per 1000 people in a population in a year. Death rate of a population is the total number of deaths that occur per 1000 people in a population.
A difference between the birth rate and death rate gives the growth rate of a population. Growth rate gives the number by which the population is increasing or decreasing. Here, the birthrate was 13 per 1000 people and death rate was 7 per 1000 people. So the net growth rate was an increase of 6 per 1000 people.