In the context of the input sentence, determine the relationship between 'Tata Teleservices' and 'Mumbai'.
Options: business division, headquarters location, owner of, developer

The regulator further said that only Bharti Airtel in Mumbai and Tata Teleservices in Delhi met the laid-down quality of service (QoS) benchmarks for call drop rate, which as per norms should be less than 2%.
headquarters location