The correct option is C The one with flat soles
Pressure(P)=Force(F)Area(A)
As both the women have same weight, so both of them will apply the same force on the ground. But flat soles having larger area compared to sandals with pointed heels, will exert lesser pressure compared to that of sandals having pointed heels. So, the sandals with pointed heels will sink more. Therefore, the woman having flat sole sandal will feel more comfortable while walking on a sandy beach.