Answer: AGREE
Step-by-step explanation:
A Monopoly faces no competition and are the only sellers of the product they sell. If firms in an industry successfully engage in collusion, the resultant effect will definitely be not unlike a Monopoly because they will set prices as a single firm, control output as a single firm and essentially run the market as a single firm.
They will sell at a rate where the Marginal Revenue curve will be below the demand curve. This will mean a higher price than a competitive market which was probably the main incentive for collusion.
A recent example would be the collusion between BMW, Daimler and Volkswagen, to hinder technological progress in improving the quality of vehicle emissions in order to reduce the cost of production and maximize profits. Thankfully this was busted by the European Commission in 2019.