Answer:
Difference threshold.
Explanation:
Difference threshold may be defined as the condition of the smallest change in the product so that the individual can takes it as different. The smallest or minimum change is noticed by the person.
The manufacturer has increased the salt content by 3%. He has increased the salt content by the smallest amount and the chips are saltier than they before. This indicates the smallest change in the chips manufacturing.
Thus, the correct answer is option (2).