Final answer:
By 2030, low-income countries are predicted to have some of the highest growth rates of contraceptive use, mainly due to their current high fertility rates and the expected increase in availability of contraception methods.
Step-by-step explanation:
Increased contraceptive availability has led experts to predict that by 2030, B) Low-income countries will have some of the highest growth rates of contraceptive use in the world. This prediction is based on the data which shows that high-fertility countries, many of which are low-income and located in sub-Saharan Africa, are expected to experience significant population growth. These countries historically have limited access to contraception, and there is a strong correlation between contraceptive availability and reduced fertility rates. As contraceptive methods become more available in these regions, the growth rate of their usage is expected to rise significantly, contributing to a slower population growth rate.
Bearing in mind that economically developed countries tend to have fewer middle-aged individuals and more older individuals, they already experience lower fertility rates and thus have less room for growth in contraceptive use. Conversely, less economically developed countries tend to have a greater proportion of young individuals, a factor that, coupled with increasing contraceptive availability, will likely lead to higher growth rates in contraceptive usage.