Questions 14-16 are based on the following monologue about GNP and GDP. You now have 15 seconds to read Questions 14-16. According to this passage, what is exactly GDP

A．It’s a new method to measure a country’s production.
B．It’s a way to study the economies of different countries.
C．It’s a new system to help make economic decisions.
D．It’s a means to understand a country’s economic changes.