Historically, Digital Realty has been a "wholesale" data center operator with a real estate focus, while Equinix has more technology DNA, as well as $7.5 billion of capital invested thus far to build out its interconnection focused "Platform Equinix."
Take context from the input text and decide on the accurate relationship between 'Equinix' and 'data center' from the options provided.
Options: distributed by, product/material produced, member of, employer