Answer:
This individual's approach to solving the problem avoids D. Functional fixedness.
Explanation:
Functional fixedness occurs when an individual is unable to see different uses for a certain object. He/she only sees the object's potential use in one particular way.
In this case the individual avoids functional fixedness because she can see a different use for the clip; she can see it as a potential tool to unlock her house, a substitute for the key.