Step 1: Hearing loss is graded by the average hearing threshold (the quietest sound the better ear can detect, measured in decibels).
Step 2: In severe hearing loss the thresholds in the better ear lie roughly between 70 and 95 dB. At this level normal conversational speech (around 50 to 60 dB) is inaudible, so the patient cannot follow ordinary speech but can still respond to shouted or amplified sound.
Step 3: Such patients benefit from powerful hearing aids but rely heavily on lip-reading, and some use sign language. This matches the clinical picture described, so the answer is severe hearing loss.
Step 4: Mild (about 26 to 40 dB) and moderate (about 41 to 70 dB) losses still allow some understanding of normal speech, while profound loss (greater than 95 dB) leaves the patient unable to hear even shouted speech. Hence those options do not fit.