Take context from the input text and decide on the accurate relationship between 'Deloitte' and 'audit' from the options provided.
Options: distribution format, stock exchange, legal form, product/material produced

Santander has picked PwC to carry out one of the most lucrative audit contracts in banking, ending a relationship with Deloitte that last year generated almost €90m (£63.9m) in fees.
product/material produced