Because of Transactions Which Take Place in the Underground Economy

Because of transactions which take place in the underground economy, the:

A) GDP calculation tends to overstate the actual value of goods sold in the economy.
B) GDP calculation tends to accurately portray the value of goods sold in the economy.
C) GDP calculation tends to understate the actual value of goods sold in the economy.
D) value of the GDP calculation will be equal to the value of the national income
Calculation.