Which type of ambiguity is caused by an error in grammatical structure?

The correct answer is based on the understanding of different types of ambiguity in language, particularly focusing on the structure and grammar. Syntactic ambiguity occurs when a sentence can be interpreted in more than one way due to its grammatical construction. This type of ambiguity arises when the arrangement of words or phrases leads to confusion about sentence meaning.

For example, consider the sentence "I saw the man with the telescope." This could mean that the speaker used a telescope to see the man or that the man the speaker saw was holding a telescope. The structure of the sentence allows for multiple interpretations due to the placement of the prepositional phrase, making it a classic case of syntactic ambiguity.

In contrast, semantic ambiguity deals with the meanings of words themselves, equivocation involves misleading use of a word or phrase with multiple meanings, and mixed metaphor refers to the blending of incompatible metaphors, causing confusion in imagery rather than structure. Thus, the distinction between these types emphasizes the role of grammatical structure in creating ambiguity, which is why syntactic ambiguity is correctly identified in this context.