The refugees and migrants in Europe reached which milestone mark recently as disclosed by the UNHCR?

The correct answer is A) 1.0 Million. In December 2015, UNHCR and IOM reported that more than one million refugees and migrants had arrived in Europe by sea during 2015. Most came via Greece, with the rest mainly via Italy, fleeing conflict in Syria, Iraq, Afghanistan and Eritrea.

Why the others fail:

• B) 1.5 Million was never the reported milestone for 2015 sea arrivals.
• C) 2.0 Million and D) 3.0 Million are far above the 2015 sea-arrival count. Watch for the cumulative or overland figures that appear in later reports, which are a different measure.

The core concept is the sea-arrival count as a humanitarian indicator, which UNHCR tracks through its Mediterranean monitoring. For Mains, connect this to the Dublin Regulation's strain on frontline states, the EU relocation quota debate, and the gap between refugee law under the 1951 Convention and border management.

Trap: Candidates mix up the 2015 sea-arrival milestone with later annual totals or with overall stock figures of refugees in Europe, and pick a higher option.