When we move along the demand curve A. income and price are held constant. B. all nonprice determinants of demand are held constant C. only quantity is held constant. D. only price is held constant.

Answer: Option 'B' is correct.

Step-by-step explanation:

Movement along the demand curve is a graphical representation which means there is a change in quantity demanded for a particular good due to change in its price.

If the price increases, quantity demanded will fall, other factors remaining constant as there is a inverse relationship between price and quantity demanded i. e. stated in "Law of Demand".

So, In this case, there is a downward movement.

So, All non price determinants of demand are held constant.

Hence, Option 'B' is correct.