75-year-old patient is brought to the emergency department (ED) after a fall while going down the stairs to his basement. He said that he just “missed” the edge of the stairs, and his foot slipped. He was wearing slippers and his glasses at the time. The lighting was dim, and he said he was tired. He has not had any falls in the past. Medical history is significant for hearing loss and macular degeneration. He wears bilateral hearing aids and glasses with bifocal lenses. He has a recent diagnosis of osteoporosis. Vital signs are normal. Physical examination and radiographs reveal a left hip fracture. Which one of the factors listed below is an intrinsic risk factor predisposing this patient toward future falls? Choose the single best answer. A. Bifocal lenses B. Loose-fitting slippers C. Macular degeneration D. Poor lighting E. Stairs to basement