The statement that is true about the changes that occur after the supermarkets merge is b, c, and e
The impact of a supermarket merger on total surplus, market price, producer surplus, market quantity, and consumer surplus can vary depending on the specific details of the merger and the market conditions.
The market price may increase as a result of reduced competition and increased market power for the merged supermarkets. Producer surplus may rise as the merged supermarkets may have more control over pricing and may benefit from increased market share.