Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

From the beginning to the ending years of a decade, the annual value of final goods and services for country X increased from €100 billion to €300 billion. Over that time period, the GDP deflator increased from 111 to 200. Over the decade, real GDP for country X increased by approximately:
Option A:50%.
Option B:67%.
Option C:200%.

Answer: B