Answer:
All three of them, A, B and C
Step-by-step explanation:
The gas station that offers a lower price provides a discount, which is a positive incentive, so that more customers purchase their gas there.
Banks do not increase security because the negative incentive is too small. The threat of bank robberies is the negative incentive, but since they rarely occur, then banks are not willing to invest in expensive security systems.
An increase in sales price is a positive incentive that will make companies produce more DVDs.