Concept:A river that cuts through steep, closely spaced contours forms a deep, narrow valley called a gorge.
Explanation:Look at the western section of R. Gembeh.
The contour lines on both sides of the river are very close together.
Closely spaced contours indicate a steep slope.
This means the river has carved a narrow and deep channel.
Such a landform is not a delta, a levee, or an undulating plain.
A delta forms where a river meets a larger water body.
A levee is a raised bank along the river channel.
An undulating plain has gentle, rolling relief with wide valleys.
Therefore, the western part of R. Gembeh flows through a gorge.
Answer:B. A gorge
