The answer is: c.There is only one way for geographers to measure development.
Developments in a certain society could be measured based on different factors, as long as these factors can be used as an indicator to the people's general well being.
GDP could be used as an indicator to measure general well being since it is very much correlated to the people's purchasing power.
Beside GDP, we can also use things such as Life expectancy, literacy rate, crime rates, etc.
