A real estate major collected information on some recent local home sales. The first $6$ lines of the database appear below. The columns correspond to the house identification number, the community name, the ZIP code, the number of acres of the property, the year the house was built, the market value, and the size of the living area $($in square feet$).$

a$.$ What does a row correspond to in this data table? How would you best describe its role: as a participant, subject, case, respondent, or experimental unit?

b$.$ How many variables are measured on each row?

c$.$ For each variable, would you describe it as primarily categorical, or quantitative? If quantitative, what are the units? If categorical, is it ordinal or simply nominal?

d$.$ Are these data a time series, or are these cross$-$sectional? Explain briefly.

$\backslash$table$[[$House$\_$ID$,$Neighborhood,Mail$\_$ZIP,Acres,Yr$\_$Built,Full$\_$Market$\_$Value,Size$],[13400536,$Greenfield Manor,$12859,1\mathrm{.}00,1967,$$$1,00,400,960],[4128001474,$Fort Amherst,$12801,0\mathrm{.}09,1961,$$$1,32,500,906],[412800344,$Dublin,$12309,1\mathrm{.}65,1993,$$$1,40,000,1620],[4128001552,$Granite Springs,$10598,0\mathrm{.}33,1969,$$$67,100,900],[412800352,$Arcady,$10562,2\mathrm{.}29,1955,$$$1,90,000,1224],[413400322,$Ormsbee,$12859,9\mathrm{.}13,1997,$$$1,26,900,1056]]$