the answer is (d). Although some digestion begins in the stomach, most digestion and absorption take place in the small intestine. The purpose of the small intestine is to finish digestion and absorb nutrients.

The small intestine has three distinct regions – the duodenum, jejunum, and ileum. Duodenum plays a vital role in the chemical digestion of chyme in preparation for absorption in the small intestine. Morever jejunum (products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here) and ileum(absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients) also perform part in the digestion. So combindally it is most apprpriate to say that the most of the digestion takes place in the small intestine.