In which area can both physical and human reasons behind low density be found?

Correct answer: An inaccessible plateau where water and transport are both limited

Direct answer: Option C is correct. Low population density can result from both physical conditions and human conditions. Step by step, an inaccessible plateau may have difficult landforms and limited water; these are physical barriers. If roads and transport are also poor, people, goods, jobs and services cannot move easily; this is a human or infrastructure-related limitation. Together these conditions discourage settlement and produce low density. Option A is wrong because a metropolis usually attracts people through jobs and services, so it is more likely to be densely populated. Option B is wrong because fertile, well-connected plains generally support farming, transport and settlement. Option D is wrong because a trading port city usually offers trade, employment and transport. Memory cue: difficult land plus scarce water and poor roads usually means sparse population.