Final answer:
The excerpt from Frederick Douglass's autobiography primarily conveys his belief that the pursuit of his desire for freedom, symbolized by his journey to Baltimore, would outweigh any potential hardships. The correct option is 3.
Step-by-step explanation:
The main idea of the excerpt from Frederick Douglass's autobiography is that Douglass's longing for freedom and fulfillment was so intense that he believed the satisfaction of reaching Baltimore would compensate for any loss of comfort experienced by leaving his home.
This suggests that Douglass was determined to escape the bounds of his current life, even if it meant facing hardship and uncertainty.
Thus, the correct answer to the student's question is that Frederick Douglass thought that the gratification of his desire would outweigh any discomfort he might experience (#3 in the provided options).