It’s not even out yet and J. Courtney Sullivan’s latest book has been optioned — by Oscar winner Reese Witherspoon, no less. Sullivan, a Milton native and Smith College grad, is the author of “Maine” and “Commencement.” Her new one, “Engagement,” to be published in June, is apparently a touching tale about a diamond engagement ring that connects five divergent relationships in surprising ways. Word in Hollywood is that Witherspoon will produce and perhaps star as part of an ensemble cast. . . . And former Del Fuego Warren Zanes is working on a biography of head Heartbreaker Tom Petty to be published by Holt in 2015. Zanes previously wrote about Dusty Springfield’s classic LP, “Dusty in Memphis,” for the 33⅓ series.