Large scale departure of people

Option B is the correct answer.

"Exodus" refers to a large-scale departure or migration of people, often used in the context of a mass movement from one place to another.

Option A: Immigration refers specifically to people moving into a country, not a large-scale departure, so it doesn't match the meaning of "departure."

Option C: Piracy refers to attacking and robbing ships, which is unrelated to a mass movement of people.

Option D: Transfer refers to moving something or someone from one place to another, but it's generally used for large-scale human departure.