As Far as Official Statistics Are Concerned,how Are Part-Time Workers

As far as official statistics are concerned,how are part-time workers categorized?

A) As unemployed,which means that the official unemployment rate tends to overstate the real level of unemployment.
B) As unemployed,which means that the official unemployment rate tends to understate the real level of unemployment.
C) As fully employed,which means that the official unemployment rate tends to overstate the real level of unemployment.
D) As fully employed,which means that the official unemployment rate tends to understate the real level of unemployment.
E) As fractions of a fully-employed worker.