Answer:
Option "D". Cost of Production.
Step-by-step explanation:
The positive experience of the customers exhibits that customer is satisfied with the commodity. Hence, a satisfied customer will always consume and demand that commodity. Therefore, the producer will induce to supply more and an increase in demand will push the price upward. Therefore, option "A", "B" and "C" tend to increase but option "d" does not relate to it.
Therefore, option "d" is correct.