Country a Had a Bigger Underground Economy Than Country B,and

Country A had a bigger underground economy than country B,and country A's citizens worked fewer hours per week than the citizens of country B.Other things being equal,how would this impact GDP comparisons between the countries?

A) It is difficult to determine since an underground economy will overstate the economic welfare of a country while fewer hours worked will understate it.
B) GDP comparisons between the countries would understate the economic welfare of country A compared to B.
C) It is difficult to determine since an underground economy will understate the economic welfare of a country while fewer hours worked will overstate it.
D) GDP comparisons between the countries would overstate the economic welfare of country A compared to B.