Two friends Jack and John appear in an interview for two vacancies in the same post. The probability of Jack's selection is (1/7) and the probability of John's selection is \((1 / 5)\). What is the probability that only one of them is selected?
i. \(2 / 7\)
ii. \(1 / 7\)
iii. \(3 / 4\)
iv. \(4 / 5\)