Take context from the input text and decide on the accurate relationship between 'Baidu' and 'Beijing' from the options provided.
Options: product/material produced, headquarters location, position held, owner of

The tax-hailing app's Chinese unit currently operates in almost 20 cities, Mr Kalanick said at an event in Beijing held by Uber investor Baidu (Xetra: A0F5DE - news ) .
headquarters location