Assuming no leak...
So, engines working but system A u/s...why...pump problem? You have 2 of them...both u/s...quite unlikely...no fluid..so you have a leak. The point is, as I already said, where is the leak, but how do you know? And even if you know...are you sure 100%???
Then..if you really can't land back and not enough fuel for the closer alternate is can be an option...but even an emergency landing below minima back to the departure airport can be an option...but if you are over the ocean, well, don't see any particular problem doing a ditching in manual reversion
