Final answer:
The osmotic pressure is reduced when monosaccharides form polysaccharides because it is dependent on the number of solute molecules, which decreases in this reaction. Option number C is correct.
Step-by-step explanation:
The student's question revolves around the factor that osmotic pressure depends on when monosaccharide molecules combine to form polysaccharide molecules. Osmotic pressure is influenced by the concentration of solutes in a solution and is directly proportional to the number of solute particles such as atoms or molecules.
This concept is key in understanding the behavior of solutions in biological systems. When monosaccharides combine into large polysaccharide molecules, the number of individual solute particles decreases, which reduces the osmotic pressure. Thus, the correct answer is: c. numbers of molecules.