In Estimating the Causal Relationship Between Sales and Price in the Following

Multiple Choice

In estimating the causal relationship between Sales and Price in the following determining function Sales_i = β₀ + β₁Price_i + U_i, what assumption in addition to E [U_i ] = 0, justifies that the estimated coefficient on Price can be interpreted as an estimate of the causal effect of Price on Sales?

A) E [Price_iU_i ] = 0
B) E [Sales_iU_i ] = 0
C) E [Price_iU_i ] = β₀
D) E [Price_iU_i ] = β₁