What role does a credit network such as Visa, MasterCard, Discover, or American Express play in your credit card purchase?

They maintain the network over which the retailer communicates with the issuer of the credit card.
They maintain the network over which the retailer communicates with the issuer of the credit card.

They issue the credit card.
They issue the credit card.

They set the price of the item you are purchasing.
They set the price of the item you are purchasing.

They maintain the network over which the retailer checks to make sure you have enough money in your account to cover the purchase.

They maintain the network over which the transaction is processed and secure the payment between the retailer and the credit card issuer. Additionally, they provide benefits such as fraud protection and rewards programs for cardholders.