Thankfully to answer this question we don't even need to fully understand the CD vs wavelength graph (this is not required MCAT knowledge but the main idea is that it helps analyze the structure of the protein). We can cross out the option A and B because osmolyte is not the protein being denatured nor represented in figure 1. We can rule out option D because the denaturing/lack thereof of disulfide bonds is not considered (none of the proteins groups were denatured by beta-mercaptoethanol) and thus this statement can't be confirmed/denied based on the information presented.