The critic found the author's latest novel to be surprisingly ______, a stark departure from the dense, ______ prose that characterized his earlier works.

✓ Correct Answer: Option A

The phrase 'a stark departure from the dense, ______ prose' indicates the blanks should be antonyms or near-antonyms. 'Dense' and 'convoluted' are synonyms for complex and difficult to understand. 'Lucid' and 'perspicuous' both mean clear and easy to understand, providing the necessary contrast.