There are choices for this question namely:
proteins
starches
disaccharides
monosaccharides
The correct answer is "monosaccharides". Monosaccharides are the most basic form of sugar that can be absorbed in the gastrointestinal tract. When we consume carbohydrates in the form of complex carbohydrates (i.e. starch) it needs to be acted upon by enzymes (initially, amylase) to break it down to smaller dextrans and disaccharides. Disaccharides will be further broken down by disaccharidases in the intestines to monosaccharides for them to be absorbed.
Proteins are acted upon by pancreatic enzymes to break it down to smaller peptides.