Procter & Gamble introduced its Duncan Hines vitamin-infused cake frosting in a small geographic area. When its competitor, General Foods, became aware of the product, it rushed to market its own Betty Crocker vitamin-infused frosting, which eclipsed the Duncan Hines product introduction. What aspect of the product development process does this scenario best demonstrate?

a. Why prototypes are so important
	b.	How idea screening can make a product a commercial success
	c.	The variety of sources for idea generation
	d.	One of the problems associated with test marketing
	e.	Why many companies engage in test marketing