A 10-year-old boy on examination was found to have scoliosis and tuft of hairs over skin of lumbar spine. He has weakness and features of lower motor neuron paralysis in both lower limbs. X-ray spine reveals the 2 lumbar veebrae at that level are fused. Most likely diagnosis is
Hemiveebra Diastematomyelia Sacrococcygeal teratoma Spinomuscular Dystrophy