Answer:A. provide evidence of a causal relationship between an independent variable and the variable to be forecast
Step-by-step explanation: Casual model tends to show the cause and effect relationship between the dependent variable to be forcasted and the independent variables upon which the dependent variable is dependent.
Casual model is frequently used in the field of Statistics and Economics when making forcasts about future investments or the cause of certain events,knowing what activities to carry out in the future.
For this case we have the following quadratic functions:
Revenue: 
Cost: 
Then, we observe that the profit is given by the following mathematical relationship:
Substituting values we have:
Making the corresponding calculations we have:
Answer:
An expression that represents the profit is:
I hope this helps you
a^6n-3n
a^3n
