Ответ:

A — 4 (Introducing St Patrick’s Day): it introduces the customs and celebrations of St Patrick’s Day.

B — 5 (A British missionary): it describes St Patrick’s life and his missionary work in Ireland.

C — 6 (The birth of the holiday): it explains where and when the first celebration took place.

D — 3 (The symbol of Ireland): it explains the connection between St Patrick’s Day, green and the shamrock.

E — 1 (Irish folklore): it describes the legend of the leprechaun.

Extra title: 2 (The origin of the traditions).