Which If the Following Is an Example of 'Third- Line

Which if the following is an example of 'third- line forcing" which is totally prohibited under s 47 of the Competition and Consumer Act?

A) A supplier refuses to supply goods to retailers unless they agree they will not sell products from a business that competes with the supplier.
B) A supplier forces a retailer to set prices that are higher than the ones set by the retailer's competitors.
C) Two competitors in the same market pay for an advertising campaign that attacks the reputation of a third party that is attempting to enter the market
D) Two competitors in the same market agree to sell goods at below cost price to drive a third party competitor out of the market.