The skill displayed by Kristin would be
b. demonstration.
Explanation:
Kristin is attending a training program on structuring problem solving which would show her real life suggestions and strategies that she must employ in her working environment for results.
This is done by her at her work and the skills that she learns fit right into her work in the current project.
This can be termed very easily as a demonstration of the skills she has learned along the way in her course and it is the due course of such demonstration.