Answer the following question on the basis of the following regression equation. (Standard errors in parentheses, n = 200.) Q = -6,500 - 100Pa+ 50Pb + .31 + .2A; R2 =.12, (2,500) (50) (30) (.1) (.08) where Q is the quantity demanded of good A; Pa= $10, price of good A; Pb= $8, price of good B; I = $12,000, per capita income; and A = $20,000, monthly advertising expenditures. 4) As a researcher, which aspect of the results would be of greatest concern? A) the negative value of the constant (i.e., -6,500) B) the relatively low impact of the competitor's price C) the fact that not all of the variables are statistically significant D) the poor