Which situation represents a proportional relationship? Select one:

A local swimming pool charges $5 per visit. There is also a $15 yearly registration fee. The total cost is proportional to the total number of days visited.

A soccer club has 15 players on every team, except for three teams which have 18 players. The number of players is proportional to the number of teams.

A bookshelf holds 25 books. The total number of books is proportional to the number of shelves in the bookcase.

Mary had $100 in the bank and each week she deposits an additional $12. The amount in her account is proportional to the number of weeks she started saving.

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