In the forth paragraph the author tells us that the young couple's apartment has "a letter-box into which would go and an electric button from which no mortal finger could coax a ring."
what does the narrator mean?

In writing about her findings in a brazilian shantytown, nancy scheper-hughes’s account of alto do cruzeiro provides a window into the terrible toll of nonconsensual organ harvesting among the poor, as well as how she herself changed over time. how might an anthropologist justify the publication of this ethnographic research when considering the problem of ethnographic authority? a. all of the poor must be given an equal voice, thus polyvocality is justification. b. anthropologists are themselves changed in fieldwork, and so honest reflexivity is justification. c. the horrific conditions made it impossible to ignore, and since she obtained informed consent, this is justification. d. authoritative writing asks us to consider what right we have to report, thus a moral challenge is justification.