Population density in Telangana is generally higher in:

The correct answer is: B) Fertile river valleys.

Hilly areas are generally less populated than fertile river valleys because they are more difficult to access and cultivate. Arid regions are also less populated because they have less water and less fertile land. Forest areas are less populated because they are often difficult to access and there is less land available for agriculture.

Fertile river valleys are generally more populated because they have more water, more fertile land, and are easier to access. This makes them ideal for agriculture and human habitation.