“Westworld” listener mail this week focuses on why William thinks he’s “the good guy,” whether host pearls are irreplaceable, how bad a mom Charlotte was, how to pronounce Serac (again), and the season’s biggest reveal: Big D is a robot. This Telegraph, covering Episode 6 of Season 3, also features email about the book young William was reading, a cryptic conversation between the Man in Black and Robert Ford, and the possibility Westworld has jumped the shark. Listener Ken L. writes in with legal jingles, a caller might be a serial killer, and Ashley informs us HBO has approved a Season 4.