Why is the word quarantine used instead of blockade?

Which of these statements best describes the ambiguity in this excerpt

What are the reasons that some europeans moved and began colonizing the new world? select all that apply: options: better economic opportunities. some were escaping religious persecution. attempting to increase their wealth, despite the hardships and risks. the new world was safer and more secure than the old world.

How did the united states surprise other delegates at the washington naval conference in 1921