Which of the following is an example of multiplier effect?

(a) The salary I get from York is sitting on my chequing account.

(b) Ticket revenue is the quantity sold multiplied by price

(c) With the new stadium built, fan capacity increased by 5 folds.

(d) Fans from around the world come to see a sport game, and their expenditure on restaurants will allow restaurant owners to pay their workers more, which the workers will buy more goods.