Buffets are all-you-can-eat restaurants with a wide selection of foods, but fast food is extremely rapid, and you typically walk in, place your order, pay, and then receive your food, which you can either eat there or take away. A drive-thru window is generally available at fast food restaurants. Fast-casual is a combination of fast food and informal eating. Fine dining has a more gourmet and refined vibe to it, with finer clothes and look expected. Food trucks or pop-up diners are examples of quick service dining. So it all depends on what you're looking for.
The answer for this question is D, for functional uses such as, holding water or to carry grains
