What problem can waterlogging cause in agriculture?

Correct answer: Roots of plants may be damaged

The direct answer is option A: waterlogging can damage plant roots. Waterlogging means that excess water remains in the soil for too long. Roots need both water and air spaces in the soil. When all spaces fill with water, roots receive too little oxygen; they may become weak, rot, or stop absorbing nutrients properly. This can reduce plant growth and damage the crop. Option A is correct because it identifies the direct biological harm caused by excess standing water. Option B is wrong because waterlogging does not always double a crop; it often lowers yield. Option C is wrong because soil cannot instantly become gold. Option D is wrong because standing water clearly affects soil, roots, plant diseases, and farm operations. Good drainage, raised beds, suitable irrigation, and timely removal of excess water can reduce the problem. Memory cue: too much water means too little air for roots.