Diana wants to replace the audio system in her car. She is considering purchasing either Brand A or Brand B audio system. The purchase price for Brand A is $300 and the price for Brand B is $275. They both are of similar quality and carry similar warranty. The installation cost is $100 for either brand. The shop will charge Diana separately for "filler" materials that it needs to use to make the new audio system "fit" into the space in Diana's car. The filler materials will cost $17.50 for Brand A and $22.40 for Brand B. Which one of the following statements is true regarding the relevance of these costs for Diana in her decision to choose one brand from among these two competing brands?

	Purchase price	Installation cost	Cost of filler materials
A	Relevant	Relevant	Irrelevant
B	Relevant	Relevant	Relevant
C	Irrelevant	Irrelevant	Irrelevant
D	Relevant	Irrelevant	Relevant
E	Irrelevant	Irrelevant	Irrelevant

	a.	A
	b.	B
	c.	C
	d.	D
	e.	E