Answer:
In my position in technical support, I was a third-tier specialist for previously unknown issues and severe problems which the first and second-tiers were unable to address.
Step-by-step explanation:
In this sentence, we learn that the person being interviewed has dealt with problems no one else could solve. This included unknown issues and severe problems which the first and second-tiers were unable to address. This statement shows that the speaker has excellent problem-solving abilities, as it provides evidence that proves this claim.