The Concentration and Herfindahl Indices Computed by the U

The concentration and Herfindahl indices computed by the U.S.Bureau of Census must be interpreted with caution because:

A) they may overstate the actual level of concentration in markets served by foreign firms.
B) they may understate the degree of concentration in local markets.
C) the definition of product classes used to define an industry affects the results.
D) All of the statements associated with this question are correct.