Movement Along vs. Shift in Supply Curve

Steps:

• Identify that movement upwards along supply curve occurs when price of rice rises, increasing quantity supplied.
• Evaluate options: A, B, D change production costs or inputs, shifting supply curve leftward.
• Recognize C increases demand (via higher incomes), raising rice price without shifting supply.
• Conclude higher price from C causes suppliers to move up existing supply curve.

Why C is correct:

• Law of demand: Higher consumer incomes shift demand curve right for normal goods like rice, increasing equilibrium price and prompting more quantity supplied along the original supply curve.

Why the others are wrong:

• A: Lowers productivity, raising costs and shifting supply left (less supplied at each price).
• B: Reduces profitability, increasing costs and shifting supply left.
• D: Raises input costs, shifting supply left (less supplied at each price).

Final answer: C