Final answer:
The best research approach depends on the specific research question and topic, but in this case, the formal approach of gathering data on dropout rates through the Internet would be the most suitable.
Step-by-step explanation:
The best research approach depends on the specific research question and topic. However, in this case, the most suitable research approach would be the formal approach of gathering data on the dropout rates of students by gender and age through the Internet using statistics gathered by the United Nations. This approach allows for accessing reliable and comprehensive data that can be analyzed independently.