The population of Ireland is predominantly of（）origin.

A.a low birth rate　
B.a high death rate
C.a low employment rate　
D.a high emigration rate

A.its small population
B.its beautiful scenery
C.its rich natural resources
D.its century-long population decline

A.it has a low birthrate
B.it has a late marriage age
C.it has an excess of females in the population
D.it has a high proportion of bachelors and spinsters of all ages