When did Evelyn Glennie's hearing become severely impaired?

Correct answer: By the age of twelve

The governing concept here is accurate recall of a key biographical detail. Evelyn’s hearing did not disappear immediately at birth or only after she became a performer. Her deafness developed during childhood and had become severe by the time she was twelve. This detail is important because it highlights the challenge she faced while beginning to build her musical identity and explains why she needed a new way to experience sound. Option B is correct. Option A gives the wrong age, while options C and D place the impairment much later and are inconsistent with the narrative of her childhood training.