MILAN (Reuters) -Credem has picked France's Worldline as the preferred bidder to buy its business to handle payment services for shopowners, the Italian bank said on Tuesday, after running a tender that involved the sector's main players. This is the latest sale of a bank's 'merchant book', meaning contracts with retailers to process electronic payments in shops. Like many other such deals in Europe, Credem's tender pitted Paris-based Worldline against Nexi, Italy's market leader and Europe's biggest payments group by transaction volumes.