Answer:
option C.
Step-by-step explanation:
The correct answer is option C.
demand curve is the curve that shows the demand for the commodity with the change in the price of the commodity.
In the question, the price of the metal used in the rollerball pen is increased this increase in the price of the metal will decrease the demand curve for the ballpoint pens.
And the demand curve for the rollerball pen would not change.