What Is the Result If the Size of the "Underground

What is the result if the size of the "underground economy" grows?

A) Real GDP will rise more rapidly than nominal GDP.
B) GDP will understate the level of economic activity.
C) GDP will overstate the level of economic activity.
D) Since GDP does not include the "underground economy",there will be no understatement or overstatement of economic activity.
E) Since the "underground economy" is included in the reported GDP,there is no issue of inaccuracy.