Mary is deciding whether to book the cheaper flight home from college after her final exams, but she's unsure when her last exam will be. She thinks there is only a 30% chance that the exam will be scheduled after the last day she can get a seat on the cheaper flight. If it is and she has to cancel the flight, she will lose $260. If she can take the cheaper flight, she will save $230. So, her Gain, for booking the cheaper flight, is a random variable. If she books the cheaper flight, what is the standard deviation of her Gain?

259.55 224.55 268.55 254.55