In my personal opinion, I think that the pregnant women should get the seat. This is because that she is carrying her weight as well as her baby's. Carrying this weight meant that her back would get hurt even more. But you also have to take in the factor that looking from this picture we don't exactly how many months pregnant she is. But from closely analysing the picture the single dad could hold his children also the fact he has children mean he probably would have to stand up because children tend to run around. The man with crutches has something to balance on as well as the old lady you has her walking stick. You could also take in the point that there are three seats meaning if you asked the other people to move there would possibly be enough spaces for the people that need or want to sit down. You also don't know whether the people sitting down have any medical problems. But in conclusion, if I had to pick someone it would be the pregnant lady.