Answer:
A. Quantity of apple demanded will decrease
Explanation:
The law of demand states that when all things are equal, when there is an increase in price there is a reduction in quantity demanded.
This is illustrated in the attached diagram
For example looking at two commodities - cooking gas and kerosene. Of the price of cooking gas goes up, people will rationally go for a lower priced alternative (kerosene). This will reduce the amount of cooking gas bought.