PLS HELP! I WILL GIVE BRAINLIEST! Read the sentence from "The Workers of Ellis Island."

The clerks—both male and female—kept a running tabulation of the number of immigrants arriving at the island for inspection each day, the disposal of their cases and their subsequent departures.

What can a reader determine from details in the sentence?

that immigrants left Ellis Island once their cases were cleared
that the job of a clerk was a difficult one
how many immigrants entered the United States each day
how clerks kept their tabulations accurate