Quiz: Data Frame Output

Output
      rank discipline yrs.since.phd yrs.service  sex salary
1     Prof          B            19          18 Male 139750
2     Prof          B            20          16 Male 173200
3 AsstProf          B             4           3 Male  79750
 [ reached 'max' / getOption("max.print") -- omitted 394 rows ]

The data frame above shows the nine-month academic salary for Assistant Professors, Associate Professors and Professors in a college in the U.S.

Which answers about the data frame printed above are correct?
Build a data frame from vectors