please answer

19) The school district is concerned that removing bus services could affect school attendance. This is an example of the A) Marginal principle B) Interdependence principle C) Sunk cost fallacy 20) Suppose the school district finds that high school attendance drops dramatically. They are willing to increase the amount of their gas cards, but doing so is expensive. They are willing to pay any amount as long as it increases attendance, but they don't want to waste money on gas cards if they don't increase attendance. So, they increase the amount of money on the gas cards by a few dollars per week. As long as attendance keeps increasing, they will continue increasing the amount on the gas cards. Once the attendance stops increasing, they will stop increasing the amount. This is an example of the A) Marginal principle B) Interdependence principle C) Opportunity cost principle