Utilize the input text as a context reference, choose the right relationship between 'Baidu' and 'search engine' from the options.
Options: chairperson, employer, product/material produced, currency

Reports earlier this year said Lyft's valuation was $2.5 billion based on the latest funding, which is still well below that of ride-sharing giant Uber, valued at $50 billion and backed by Chinese search engine giant Baidu (Xetra: A0F5DE - news ) , among others.
product/material produced