____ crowded city New York is! ?

The correct answer to the question, "____ crowded city New York is!" is A) "What a." This expression is an example of an exclamatory structure, which is used to express strong feelings or emphasize a particular quality.

In English, the phrase "What a" is commonly used to make enthusiastic or emphatic statements about a noun. For instance, saying "What a beautiful day!" underscores the speaker’s admiration for the day, much like "What a crowded city New York is!" emphasizes the degree of crowding in New York.

The option B) "How" is also used for exclamations, but it typically modifies adjectives or adverbs and is generally structured as "How + adjective/adverb + subject + verb." For example, "How crowded New York is!" While this conveys a similar sentiment, it doesn't fit the original sentence structure.

Choice C) "That" and D) "What is" do not form appropriate exclamatory phrases in this context. "That" does not fit grammatically, and "What is" would suggest a question rather than an excited statement. Therefore, only "What a" maintains the intended emphasis on New York’s crowdedness while preserving the correct grammatical structure.