Answer:

Introduction:
Photoresist is a light-sensitive material used in the process of photolithography. It is applied as a thin layer on a substrate and is used to transfer patterns onto the surface of the substrate. During the development process, certain parts of the photoresist layer need to be removed to create the desired pattern. The choice of the developer solution plays a crucial role in this process.

Explanation:
The correct option for removing a few parts of the photoresist layer is acidic solution (Option A). This is because the photoresist material is typically sensitive to alkaline solutions and resistant to acidic solutions.

Acidic Solution:
An acidic solution, such as a developer solution containing an acid, is used to selectively remove the exposed or unexposed regions of the photoresist layer. The acid reacts with the photoresist material, causing it to dissolve or disintegrate, thus removing the desired parts of the layer. The acid can break the chemical bonds within the photoresist molecules, leading to their removal.

Neutral Solution:
A neutral solution, such as pure water or diluted water, is not effective in removing the photoresist layer. This is because the photoresist material is usually not soluble in neutral solutions. Pure water or diluted water does not have the necessary chemical reactivity to dissolve or disintegrate the photoresist material.

Conclusion:
In conclusion, an acidic solution is the correct option for removing certain parts of the photoresist layer. The acid in the developer solution reacts with the photoresist material, causing it to dissolve or disintegrate, thereby removing the desired regions. Neutral solutions like pure water or diluted water are not effective in removing the photoresist layer as they lack the necessary chemical reactivity.