What is the relationship between MasterCard and purchase in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

And while you might be tempted to purchase a generic gift card from a payment network like Visa, MasterCard or American Express, be aware that these cards can carry a fee that will reduce or eliminate any bonus cash back you were hoping to earn.

Answer: headquarters_location