By the time that the young bear grew to full adulthood , his parents and siblings had moved on to better hunting and fishing grounds . Yet , alas , the young bear still had an attachment to this place that he called home - as it was really the only home that he had ever known . Years went by .

Generate a question about the above context.
Why did the young bear 's family move on to better hunting and fishing grounds ?
Available options:
(a). The place they all lived never ran out of prey as time passed .
(b). The place they all lived had a lot of prey for them to eat .
(c). The place they all lived did n't have a lot of prey for them to eat .
(d). None of the above choices .