Which letter pair in the word "chimpanzee" represents a digraph?

A digraph is a combination of two letters that together represent one sound. In the word "chimpanzee," the letter pair "ch" represents a single sound, which is the "ch" sound found at the beginning of the word. This is different from the other letter pairs in the word, which either do not form a single sound or consist of letters that are pronounced individually. For instance, "mi," "na," and "ze" each contain sounds that can be broken down into their individual letters rather than creating a single phonetic sound. Therefore, "ch" is the only pair among the options that fits the definition of a digraph in this context.