Final answer:
An abandoned, cutoff meander loop is known as an Oxbow lake, which occurs when a river bend is isolated from the main flow.
Step-by-step explanation:
A meander loop that becomes abandoned due to the process of river erosion and deposition is known as an Oxbow lake. This occurs when a river creates a bend due to the water flowing along a curved path. Over time, the loop may get cut off from the main course of the river, especially during flood events, forming an isolated water body. The appropriate term for an abandoned, cutoff meander loop is A) Oxbow lake.