Suppose the real GDP of country X was $800 billion in 2020 whereas its population in the same year was 0.5 billion. In 2021, the real GDP of this country increased to $900 billion whereas its population increased to 0.6 billion. What is the economic growth rate of real GDP per person in country X?

Select one:

A.-6.25%

B.1.2%

C.12.5%

D.6.25%

E.-12.5%