Margot is studying the yield of bushels of wheat in comparison to the amount of rainfall, in inches, that occurs. She finds the linear regression equation to be y = 47.3 +0.78x. 
 If an additional 1 inch of rain fell, how many MORE bushels of wheat would be yielded?
 A) 0.78 
 B) 47.3 
 C) 48.08 
 D) 60.64