b. <em>he describes the event unemotionally to avoid bias and sentiment</em>. This is the correct answer.
Frederick Douglass, a former slave, wrote this memoir in 1845. The event he describes is related to the moment he left a plantation- Colonel Lloyd's - and the fact he was being carried to Baltimore by sail. There is not any emotional language in this description. As this narrative was considered a treatise against abolition, the writer must have avoided any sentimental language.
These options are not right:
a. he describes the event chronologically to make the account factual. ( The event is described but chronology is not stated).
c. he uses words such as remember to set a sad, nostalgic tone. ( The word remember is mentioned because it is a memoir. The words does not necessarily indicate any nostalgic tone).
d. he uses nautical terms, such as aft, to establish his credibility. ( The writer's credibility will not be reflected by his use of this specific vocabulary).