What role do villi play in absorption

"The small intestine contains small finger-like projections of tissue called villi which increase the surface area of the intestine and contain specialized cells that transport substances into the bloodstream. Although these villi do not aid in the digestion of nutrients, they do help with nutrient absorption. The cells of the villi and another part of the small intestine, known as the crypts, transport food from the digestive tract into the bloodstream, where they can be used by the body. The villi aid in absorption by increasing the surface area of the intestine and contain specialized cells which transport different types of nutrients into the blood."
 http://livehealthy.chron.com/importance-villi-small-intestine-digestion-nutrients-3923.html

The correct answer is b

The correct answer is d