The correct option is B The potato cores will lose mass.
Potato cores with an osmolarity of 0.5 M are placed in a 1.0 M solution of sucrose water overnight. In this case, the osmolarity of potato core is less than the solution present outside, which means the solution is hypertonic as compared to potato cores. Thus water will move from a higher concentration of solvent i.e. potato core to lower concentration i.e. outside solution. Thus potato cores will lose mass. Therefore, option B is the correct answer.