Select each situation that can represent a proportional relationship

The price of buying x gallons of gas at $3 a gallon.

The total amount of weight a kitten gains in w weeks when it gains 4 ounces per week and started at a weight of 6 ounces.

The price of renting a scooter for m miles when it costs $0.75 per mile plus a base fee of $2.50.

The total amount of money a child earns from doing chores when she earns $10 a week for w weeks.
Plz help!