The Effect of Undocumented Immigrants on the Economy of the United

The effect of undocumented immigrants on the economy of the United States:

A) is a settled question among economists.
B) has not yet been a subject of study, so no data exists.
C) appears to push down wages for those at the bottom of the economic ladder.
D) is negligible in terms of consumer spending and additional tax revenue.
E) is limited because there are only a few thousand working in the United States.