Answer:D. Raw chemicals
Step-by-step explanation: A value system in this context is the system which comprise of different processes or points where improvements or values are added to the initial materials as it flows along.
The starting point will be the point from where the raw materials are being introduced or added before the flow continue with consistent value addition.
This is similar to what happens in production or manufacturing process where the process starts with the addition of raw materials to the different points where value addition is taking place till it come out a finished product with improved value.
1) a modle
2) in a classroom
3) where everything is located
