The article titled "The Future of AI" was published last month.
Correct: D
Option D is correct. Titles of short works like articles, essays, poems, or chapters are enclosed in double quotation marks. No comma is needed between 'titled' and the beginning of the title, nor after the closing quotation mark, because the title phrase functions as an integral part of the sentence's subject. Option A uses single quotation marks incorrectly for a title. Options B and C incorrectly insert commas.