The correct answer is: C. (A) is correct but (R) is incorrect.
Assertion (A) is correct. The demand for a commodity refers to the quantity of the commodity that consumers are willing and able to purchase at a certain price during any particular period.
Reason (R) is incorrect. The contraction of demand is the result of a decrease in the price of the good concerned. When the price of a good decreases, consumers are willing and able to purchase more of the good. This is known as the law of demand.
Here is a diagram that illustrates the law of demand:
[Diagram of a demand curve]
The demand curve shows the relationship between the price of a good and the quantity demanded of that good. The demand curve slopes downward, which means that consumers are willing and able to purchase more of a good when the price of the good decreases.
I hope this explanation is helpful! Please let me know if you have any other questions.