Given:
The population density of Iceland, in people per square kilometer of land area, increased from 2.5 in 1990 to  3.3 in 2014.
Land area of Iceland = 100,250 square kilometers.
To find:
The Iceland's population increase from 1990 to 2014.
Solution:
Land area of Iceland is constant, i.e., 100,250 square kilometers.
The population density of Iceland, in people per square kilometer of land area in 1990 is 2.5. Â So, the population in 1990 is
[tex]2.5\times 100,250=250,625[/tex]
population density of Iceland, in people per square kilometer of land area in 2014 is 3.3. Â So, the population in 2014 is
[tex]3.3\times 100,250=330,825[/tex]
The Iceland's population increase from 1990 to 2014 is
[tex]330,825-250,625=80,200[/tex]
Therefore, the correct option is D.