What punctuation belongs at the end of a business letter

What type of external conflict occurs in the excerpt from “stephen crane’s own story”? it was now that the first mate showed a sign of losing his grip. to us who were trying in all stages of competence and experience to launch the lifeboat he raged in all terms of fiery satire and hammerlike abuse. but the boat moved at last and swung down toward the water. a. person versus person b. person versus nature c. person versus society d. person versus self i think its either b or d.