Concept:The middle course of a river is marked by a wider valley and depositional features like flood plains.
Explanation:In the upper course, the river forms V-shaped valleys, rapids, and interlocking spurs.
In the middle course, lateral erosion widens the valley into a broad, open U-shaped form, and the river deposits materials to create flood plains.
Distributaries and broad interfluves are features of the lower/deltaic course, not the middle course.
Answer:A. U-shaped valley and flood plains