In a 1961 treatise, urban planner Jane Jacobs identified the key components of a vibrant city neighborhood. Her criteria for safety and community were ______ to ensure "eyes on the street," to foster casual public contact, and to assimilate children into city life.
Which choice completes the text so that it conforms to the conventions of Standard English?
threefold to
threefold. To
threefold; to
threefold: to
Correct Answer: D
Choice D is the best answer. It correctly uses a colon to introduce a list that elaborates on the preceding clause. The phrase "Her criteria...were threefold" sets up an expectation for an explanation or list, which the colon provides.
Choice A is incorrect because it lacks punctuation to separate the introductory clause from the list. Choice B is incorrect because a period creates a sentence fragment ("To ensure...") that cannot stand alone. Choice C is incorrect because a semicolon is typically used to join independent clauses, not to introduce a list of infinitive phrases.