Final answer:
The country with the most controversy about 2016 growth among the analyst community is the United States. The correct option is a.
Step-by-step explanation:
The country with the most controversy among the analyst community about 2016 growth is A) United States.
According to the information provided, the purple line represents historic real GDP growth, the white line represents the consensus estimated real GDP growth, the red line represents the most pessimistic analyst forecast, and the green line represents the most optimistic analyst forecast.
Therefore, by comparing the forecasted lines, the country with the widest range of forecasts and consequently the most controversy among the analysts is the United States. The correct option is a.