Refer to the input text as context and select the correct relationship between 'grocery' and 'Walmart' from the available options.
Options: platform, location of formation, subsidiary, operator

Walmart will offer the online grocery pickup at select stores in Atlanta; Charlotte and Fayetteville, N.C.; Salt Lake City; Ogden, Utah; Nashville, Tenn.; Tucson, Ariz.; and Colorado Springs, Colo.
operator