All of them. Is a good practice to choose wisely your peers with who you have channels. always study their peers too and with who they have also channels. That way you can have a map of your possible routes. Usually wallet apps "learn" the previous payments paths and try to take the same if were successful. Is named mission control. But not always the previous path will repeat OK. So you will have the option to reset the mission control and switch between bidirectional or apriori path finding. But use this only in rare cases when you do not have another option. Some wallet apps let you also to choose the first hops / channels through which you want to make the payment. That could help sometimes with a faster payment.