There were reasons why she was the worst possible choice.
"She became the only possible choice the first moment I saw her."
"Yes," he said, as if it were the only possible choice for such a mission.
Clearly, you are the only possible choice as his successor.
That makes you the best possible choice in some respects.
Both were thought to be possible choices for wife number six.
But he wanted that to be their last possible choice.
Others may lay out every possible choice, then say the decision is up to you.
In any situation, there are a number of possible choices.
I've thought a lot about it, and I arrived at two possible choices.