Which factor is most likely to shift the supply curve for milk to the left?

• A. A decrease in the price of milk
• B. A decrease in consumer income
• C. An increase in the price of cattle feed
• D. A technological improvement in milking machines

Answer: (C)

Verified step by step guidance

1. Understand that a supply curve shows the relationship between the price of a good and the quantity producers are willing to supply, holding other factors constant.
2. Recall that a shift to the left in the supply curve means a decrease in supply at every price level, which can be caused by an increase in production costs or other negative supply shocks.
3. Analyze each option to see if it affects supply or demand: a decrease in the price of milk affects quantity supplied (movement along the curve), not the supply curve itself; a decrease in consumer income affects demand, not supply.
4. Recognize that an increase in the price of cattle feed raises production costs for milk producers, which reduces their willingness or ability to supply milk at previous prices, shifting the supply curve to the left.
5. Note that a technological improvement in milking machines would lower production costs, increasing supply and shifting the supply curve to the right, not left.