The correct answer is option 'D' - Concentrated solution.

When a large amount of solute dissolves in a given amount of solvent, it forms a concentrated solution. Let's understand this in detail:

1. **Solute and Solvent:**
- Solute: It is the substance that gets dissolved in a solvent to form a solution. It is present in a smaller amount.
- Solvent: It is the substance in which the solute dissolves. It is present in a larger amount.

2. **Concentration:**
- Concentration refers to the amount of solute present in a solution per unit volume or mass of the solution.
- It can be expressed in various ways, such as molarity, molality, mass percent, etc.
- In the context of this question, when a large amount of solute is dissolved in a given amount of solvent, it means that the concentration of the solute in the solution is high.

3. **Dilute Solution:**
- A dilute solution contains a small amount of solute dissolved in a larger amount of solvent.
- In other words, the concentration of the solute in a dilute solution is low.
- This is the opposite of the given scenario, where a large amount of solute dissolves in a given amount of solvent.

4. **Saturated Solution:**
- A saturated solution is one in which the maximum amount of solute has dissolved in the solvent at a given temperature and pressure.
- Adding more solute to a saturated solution will not result in further dissolution. The excess solute will remain undissolved.
- The given scenario does not mention reaching the saturation point, so it is not a saturated solution.

5. **Aqueous Solution:**
- An aqueous solution is one where water is the solvent.
- The given scenario does not specify the solvent being water, so it is not necessarily an aqueous solution.

6. **Concentrated Solution:**
- A concentrated solution contains a large amount of solute dissolved in a given amount of solvent.
- The concentration of the solute in a concentrated solution is high.
- This matches the given scenario where a large amount of solute dissolves in a given amount of solvent.

Therefore, the correct answer is option 'D' - Concentrated solution, as it best describes the situation where a large amount of solute has dissolved in a given amount of solvent.