A decrease in the price of oranges would lead to a
a. a movement down and to the left along the supply curve for oranges.
This is because a decrease in price typically results in a decrease in the quantity supplied, which corresponds to a movement along the supply curve. A decrease in price would not cause an increase in supply (option b), nor would it directly relate to changes in input prices (option c) or a movement up and to the right along the supply curve (option d).