“Pride and Prejudice” may be Jane Austen’s most beloved novel. Now it has gotten a 21st century makeover. The book is called “Eligible” and it’s written by Curtis Sittenfeld, the bestselling author of “Prep” and “American Wife.” The story transports the Bennet sisters from the English countryside to the affluent suburbs of Cincinnati. In this modern retelling, barbecues have replaced balls, and texting is the preferred form of written communication. Yet tensions over class and gender remain — along with the struggle to marry on one’s own terms — if at all. Curtis Sittenfeld on remaking a classic and the enduring appeal of Jane Austen.