Final answer:
The type of function that best models the data is quadratic, because the production cost decreases to a minimum of $6,000 and then increases.
Step-by-step explanation:
The type of function that best models the data is option 3) quadratic, because the production cost decreases to a minimum of $6,000 and then increases.
Quadratic functions have a parabolic shape, and they can have a minimum or a maximum point. In this case, the production cost starts at $6,000 for 10 computers, decreases to a minimum of $5,000 for 20 computers, and then increases again. This trend matches the shape of a quadratic function.
Therefore, the best model for the data is a quadratic function that has a minimum point at $6,000 for 20 computers and then increases.