Bhangar and Khadar are terms related to what?

Correct answer: Soil of alluvial plains

The direct answer is A, soil of alluvial plains. Bhangar and Khadar are terms used for two parts or age groups of the alluvial soil found in the Northern Plains. Bhangar is older alluvium, usually lying on slightly higher terraces and containing old deposits. Khadar is newer alluvium deposited by rivers during floods on the lower floodplains, so it is generally renewed more often and is usually more fertile. The reasoning is: river carries sediment → sediment is deposited on plains → old deposits are Bhangar and new flood deposits are Khadar. Option A is correct. Option B, coral islands, concerns marine coral formations such as Lakshadweep, not river-deposited plain soil. Option C, volcanic rock, forms from cooled lava and is unrelated to the Bhangar–Khadar distinction. Option D, glaciers, are masses of moving ice; they are not soil categories. Remember the contrast: Bhangar = old alluvium, Khadar = new alluvium. ‘Khadar’ can be linked with fresh deposits brought by recurring floods.