A) I guessed the ACS because it is the survey that an American is most likely to receive.
The ACS is a huge survey that replaces the long form in the 2010 Census. There are a number of potential quirks with such a survey, and there is great international interest to see how it will work out.
B) The USBC conducts many other surveys, e.g., the Current Population Survey, which gives the unemployment rate There's a list on the USBC website. As well, there is a tool (which I have not used) that lets you make information from many surveys, including the ACS: http://dataferrett.census.gov/
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