The Following Linear Demand Specification Is Estimated for Conlan Enterprises,a $Q = a + b P + c M + d P _ { R }$

The following linear demand specification is estimated for Conlan Enterprises,a price-setting firm: $Q = a + b P + c M + d P _ { R }$ where Q is the quantity demanded of the product Conlan Enterprises sells,P is the price of that product,M is income,and $P _ { R }$ is the price of a related product.The results of the estimation are presented below: Given the above,at the 1% level of significance,which estimates are statistically significant?

A) All are statistically significant
B) All but $\hat { a }$ are statistically significant
C) Only $\hat { a } , \hat { b } \text {, and } \hat { c }$ are statistically significant
D) Only $\hat { a }$ is statistically significant
E) All but $\hat { b } \text { and } \hat { d }$ are statistically significant