Which of the Following Is an Example of a Contract

Which of the following is an example of a contract which is probably illegal at common law?

A) Bill sells cigarettes to someone with lung cancer.
B) Bill arranges to transport milk across the border from Victoria to New South Wales.
C) Bill arranges to buy a news agency business and has a clause in the contract which restricts the seller from carrying on the same business in Sydney for 5 years.
D) Bill donates $4000 to a charity to get an award in the Australia Day Honours list.