Which word is incorrect in the following sentence: Of the many people what she interviewed; she chose the one with the most experience?

The word "what" is incorrect in the sentence because it is improperly used in this context. The phrase should use "that" instead of "what" to properly introduce the relative clause. The correct form would be "Of the many people that she interviewed, she chose the one with the most experience." "That" acts as a defining relative pronoun, which is suitable here because it specifies which group of people is being discussed.

In contrast, "what" is used to refer to a thing or things that are not specified, which does not correctly apply to the context of identifying specific individuals. The other elements of the sentence—"Of the," "with," and "most experience"—are grammatically correct and appropriately used, which is why they do not affect the overall structure negatively.