Which lake may form when an old river bend is cut off?

Correct answer: Oxbow lake

The direct answer is A, an oxbow lake. A meander is a curved bend in a river. As the outer banks are eroded and sediment is deposited on inner banks, the bend can become very narrow at its neck. During a flood or strong flow, the river may cut through the neck and take a straighter route. The abandoned curved loop then becomes a separate water body called an oxbow lake. Option A is correct because it specifically describes a cut-off old river bend. Option B, a lava lake, contains molten volcanic rock in a volcanic crater and is not produced by river-bend cutting. Option C is wrong because an oxbow lake is not defined as a salt-water lake; it is usually a freshwater lake, though its exact water condition can vary. Option D is wrong because a glacial lake is made by glacier erosion or melting, not by a meander being cut off. The sequence to remember is: meander grows, neck is cut, loop is abandoned, oxbow lake forms. This is a common river-landform question.