Answer:
The answer is D) Once only available as delightful treats and specialty items on bakery shelves, delicious doughnuts are now on grocery store shelves everywhere!
Step-by-step explanation:
Having a bias toward something means showing preference for it. The word "bias" indicates that a person likes or dislikes something very much when compared to something else. Thus, they can be biased against something, or biased in favor of/toward something.
What we need to do to answer this question is merely identify the sentence in which the speaker expresses his preference for something. All the sentences seem to talk about doughnuts, their history, how they can be categorized and so on. But the last option "Once only available as delightful treats and specialty items on bakery shelves, delicious doughnuts are now on grocery store shelves everywhere!" shows us that the author appreciates doughnuts. We may conclude that due to the words employed - delightful, treats, delicious. They express the way the author views doughnuts - as something good, something scrumptious. He/she could have remained neutral, using words that didn't shine a positive light on doughnuts. But the author chose words that convey that he/she likes doughnuts.