Concept:Changes in demand are caused by factors other than the price of the commodity itself.
Explanation:These factors are known as demand shifters.
They include consumer preferences (taste), changes in income, taxation, advertisement, population, weather conditions, and the price of other commodities.
When any of these factors change, the entire demand curve shifts either to the right or to the left.
Therefore, all the listed matters (I, II, III, IV) can account for changes in demand.
Answer:D. I, II, III, IV