Explanation

Tuvalu, the low-lying Pacific island nation whose highest point is barely 4.6 metres above sea level, faces existential submergence from sea-level rise driven by melting ice caps and thermal expansion of the oceans. It is the flagship example in discussions of climate-change-induced displacement. The other options — potatoes, equatorial snow, and a new technology — have no connection to Tuvalu. The melting-ice-caps option is correct.