Based on these regression results from Lab 5.2 Excel, Evaluating the Relationship Between Sales and R\&D Expenditures: Testing for a Nonlinear Relationship. how can the relationshis hetween sales and R\&D be best explained? R\&D Expenditures are positively associated with sales. R\&D Expenditures are positively associated with sales at an increasing rate. C) R\&D Expenditures are positively associated with sales at a decreasing rate. (D) R\&D Expenditures are negatively associated with sales