We use the following regression model to study the effect of changing a product's sales price P on the demand of the product D for a home company. In the regression, sales price of a similar product by the home company's competitor, denoted by PC, is also considered. How would you interpret coefficient ? Group of answer choices A unit increase of the home company's price would change the demand by , if the competitor would not change their price. A unit increase of the competitor's price would change the demand by , if the home company would not change their price. A unit increase of the competitor's price would change the demand by , taking into account that the home company would change their price in reaction to the competitor's price change. A unit increase of the home company's price would change the demand by , taking into account that the competitor would change their price in reaction to the home company's price change