Answer:
b. matches the needs of the target market.
Explanation:
Marketing Mix refers to set of 4Ps of marketing : Product, Place, Price, promotion. It is a combined policy set of businesses, used to promote its brand or product.
The marketing mix purpose is to : address the right customers, with the right product, at the right price, with the right promotion strategy.
So, the main underlying guiding principle of Marketing Mix - is it's compatibility & match up with the needs of target market.