Drea is the director of marketing for a company that makes mobile phone batteries. She has been asked to evaluate international business opportunities. She initially recommended that her company focus on expanding to countries in the European Union because of their high gross domestic product $($GDP$),$ but recently she learned that cell phone penetration is an indication of $\_\_\_\_\_\_\_$ growth, so she reworked her recommendation to include India and parts of Africa.

economic

population

landline

middle$-$class