This is the 3381st most frequent Polish word.
wyborem
"Choice" or "selection" (instrumental case of "wybór").
In this sentence, 'wyborem' is used as a noun in the instrumental case, indicating a particular choice that was difficult.
To był trudny wyborem dla mnie.
That was a difficult choice for me.
Here, 'wyborem' is used as a predicate, underlining what was selected.
Jeden z tych projektów musieliśmy wybrać jako wyborem.
We had to select one of these projects as the choice.
In this example, 'wyborem' reflects a state or condition described metaphorically as a choice and is in the context of a figurative expression.