An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because _____________.

Osmosis is the flow of the solvent from higher concentration to lower concentration through a semipermeable layer.

Unripe mango has a higher concentration of water and salt solution has a lower concentration of water.

Thus, water flows from mango to salt solution due to osmosis, as a result, mango shrivels.

Thus, Option (iv) is the correct answer.