Julia, the owner of a pizza restaurant chain, would like to predict the sales of her recent specialty, a Mediterranean flatbread pizza. She has gathered data on monthly sales of the Mediterranean flatbread pizza at her restaurant as well as information related to the average price of flatbread pizzas, the monthly advertising expenditures, and the disposable income per household in the areas surrounding the restaurants. What is the variable that Julia is trying to predict to predict? Average price of her Mediterranean flatbread pizzas. Monthly sales of her Mediterranean flatbread pizza. Average household disposable income Monthly advertising expenditures