Take context from the input text and decide on the accurate relationship between 'MasterCard' and 'purchase' from the options provided.
Options: member of, operator, headquarters location, founded by

Samuel Ashitey said the MasterCard network in over 220 million shops and businesses in over 210 countries, the SAA Voyager credit card is by far the fastest way to earn miles with a ticket purchase to fly on South Africa Airways or make qualified merchant purchase.
headquarters location