The correct options are
A Floodplains
C Meanders
D Ox-bow lakes
In the mature stage or middle course of the river, the flow is relatively slower than in the youthful stage. This causes erosion on the sides of the rivers, unlike vertical erosion which is dominant in the upper reaches. Some depositional landforms can be observed in this stage. For example, ox-bow lakes, meanders, and floodplains are common landforms in this stage.