Correct Answer: Least

Solution : The correct choice is the third option .

The word fundamental implies something essential, basic, or central. On the other hand, least denotes the smallest in amount, extent, or significance. In this context, if something is fundamental, it is of great importance, while if it is the least, it is of minimal importance.

The meanings of the other options are as follows:

• Impact refers to a forceful effect or influence.
• Neutral suggests a lack of bias or preference.
• Link refers to a connection or relationship between things.