Examine the following conversation: Customer: What you say is important, all right, but how do I know that these chairs will take wear and tear the way you say they will? Salesperson: The durability of a chair is an important factor to consider. That's why all Crest chairs have reinforced plastic webbing seats. Furniture Dealer's Weekly states that the plastic webbing used in Crest chairs is 32 percent more effective in preventing sagging chair seats than fabric webbing. This means that your chairs will last longer and will take the wear and tear that your customers are concerned about. Look at each sentence in this conversation and state if it is
a. An expansion of the benefit.
b. A restatement of the benefit.
c. A proof of the benefit.