I think it is C. However, it should just be rock and water/ice.
Entende-se por carta informal a missiva trocada entre pessoas com um relacionamento próximo e entre as quais existe familiaridade (parentes, amigos, colegas, etc.). São cartas que utilizam um estilo coloquial, apresentando o texto características de subjectividade.
<em>Answer:</em>
<em>As the Industrial Revolution was a shift from the agrarian society, people migrated from villages in search of jobs to places where factories were established. This shifting of rural people led to urbanization and increase in the population of towns. The concentration of labour in factories has increased urbanization and the size of settlements, to serve and house the factory workers.</em>
It is connected by the Korea Strait!
Hope this helps you out! Thanks! :)