Which option gives a correct cause and example of lake formation?

Correct answer: Oxbow lake by meander cut off

Direct answer: Option A is correct. An oxbow lake forms when a river meander, or curved bend, becomes cut off from the main river channel. First, a river develops a loop-shaped bend. Erosion usually acts more strongly on the outer bank, while deposition occurs on the inner bank. Over time, the narrow neck of the loop becomes thinner. During high flow or flooding, the river may cut through the neck and take a straighter path. The old curved loop is then separated from the main channel and remains as an oxbow lake. Option A correctly matches the cause with the lake type. Option B is wrong because a glacial lake is formed by glacial erosion or deposition, not by a sea wave. Option C is wrong because salt does not create a mountain lake in this manner. Option D is wrong because smoke cannot form a coastal lake; coastal lakes or lagoons have connections with coastal processes such as sand bars and sea action. Exam cue: cut-off meander makes an oxbow lake, usually curved like a bow.