The correct answer is all of the above.
Mrs Wylie is placed on a vitamin B12 supplement because she has neurologic symptoms consistent with vitamin B12 deficiency, she has a history of antacid use and because of her age.
According to the information provided, Mrs Wylie is experiencing some neurological symptoms including difficulty walking, pain and weakness in her legs, loss of feeling in her fingers and feet and occasional constipation. She also takes some over-the-counter medications, such as antacid, that help her with problems regarding her stomach acid, such as heartburn, indigestion or acid reflux. Finally, Mrs Wylie's age requires a daily intake of B12 supplement (78 years old).