Downward movement along the demand curve is caused by _____.

The correct answer is Option (1) → Fall in price of the given commodity.

A downward movement along the demand curve (also called extension of demand) happens when:

• The price of the given commodity decreases, and

• As a result, quantity demanded increases

This is a direct result of the law of demand, which states that there is an inverse relationship between the price of a commodity and its quantity demanded, ceteris paribus (holding other factors constant).

A shift of the demand curve is caused by changes in other factors, such as the price of substitute or complementary goods, consumer income, or consumer preferences.

Why other options are incorrect:

• Rise in the price of substitute goods → Causes a rightward shift in demand curve, not a movement along it.

• Rise in price of the given commodity → Leads to an upward movement (contraction), not downward.

• Fall in price of substitute goods → Causes a leftward shift in demand curve.