Answer: The region that is named Northern Ireland is B.
Explanation: Northern Ireland is a country and a constituent part of the United Kingdom, which is also conformed by Scotland, Wales and Great Britain. Its capital city is Belfast. Moreover, as the picture shows, Northern Ireland shares a border to the west and south with the Republic of Ireland, which is represented by C. in the map. While the Republic of Ireland is located on the south of the island of Ireland, Northern Ireland is situated in the north-east of the island.