Concept:A change in quantity demanded means a movement along the same demand curve due to a change in the commodity’s own price.
Explanation:When only the price of a commodity changes, consumers buy more or less of it, causing a movement along the demand curve.
This is known as a change in quantity demanded.
Factors like population, income, and taste cause a shift of the whole demand curve, not a movement along it.
Therefore, the determining factor here is the price of the commodity itself.
Answer:C. price of the commodity