Help needed on Probability & PC

Q's on Probability & PC Two couples & a single person are settled at random in a row of five chairs. What is the probability that neither of the couples sits together in adjacent chairs? A. 1/5 B. 1/4 C. 3/8 D. 2/5 E. 1/2 Out of the 7 models, all of different heights, five models will be cho...