To study osmosis, a student placed a thin potato slice in a salt solution. the slice became soft and shriveled. then, he placed the shriveled slice in water. the slice regained its original shape. based on the observations, which of these statements is correct? a) the slice regained its shape because salt moved into the potato. b) the potato slice shriveled because water moved from the salt solution into the slice. c) the potato slice shriveled because water moved out of the slice into the salt solution. d) the slice regained its shape because the concentration of salt inside and outside the slice became equal.

Osmosis is the movement of water from a region of higher water concentration to a region of lower water concentration across a selectively permeable membrane. Simply put, water passes across membranes into areas where more 'stuff' is dissolved.
In this system, The slice shriveled in salt solution. That means water left the potato's cells. Then the slice regained its shape when placed in pure water. That means water moved back into the cell. 
A) incorrect. Salt does not move across the membrane
B) incorrect. If water moved into the slice, it would have swelled, not shriveled
C) correct. Water moved out of the cell into the more concentrated salt solution
D)incorrect. Placing the slice in pure water does not balance the concentration of salt between the cells and the water.

Idont know but good luck; )