Respuesta :
Well, you missed the actual option and that's "He knew that at fifty below spittle crackled on the snow, but this spittle had cracked in the air. Without any doubt it was colder than fifty below". that's more precise and detailed.
A."[The cold] did not lead [the man] to meditate upon his frailty as a creature of temperature . . . it did not lead him to the conjectural field of immortality and man's place in the universe." Literary and artistic naturalism aims at accuracy and objectivity and cultivates realistic and even sordid portrayals of people and their environment.