In General, Why Did Large Numbers of Emigrants Depart from Rural

In general, why did large numbers of emigrants depart from rural Ireland and Scandinavia?

A) The population was expanding so rapidly that these countries did not have enough jobs at which to employ the growing labor pool.
B) Because none of these countries was an independent, democratic state, people left to find more freedom.
C) American entrepreneurs who needed workers targeted these people and gave them large signing bonuses to emigrate.
D) These three areas lagged behind the rest of Europe in unionization and workers' rights.