Answer : The correct option is, a large amount of solute.
Explanation :
As we know that the saturated solution is made when the maximum amount of solute dissolved in the solvent.
In unsaturated solution, the undissolved substance is settle down at the bottom that means no more solute is dissolved in the solvent.
The concentrated solution means that a large amount of solute present in the solution.
Hence, in a concentrated solution there is a large amount of solute.