The correct choice among the given regarding isotonic solutions is /are:

(a) Solute and solvent both are same
(b) Osmotic pressure is same
(c) Solute and solvent may or may not be same
(d) Solute is always same solvent may be different

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Hint: For isotonic solution, osmatic pressure is same
The two solutions having same osmotic pressure are known as isotonic solutions. The solute and solvent particles may or may not be same but osmotic pressure must be same.
Hence, option second is the correct answer.