What is the relationship between 'Sabadell' and 'euro' in the context of the input sentence.
Options: chief executive officer, currency, industry, distribution format

MADRID, Sept 14 (Reuters) - Spanish bank Sabadell is considering making a bid for an 18 billion euro ($20.4 billion) mortgage portfolio held by British nationalised banks Northern Rock and Bradford & Bingley, a source familiar with the process said on Monday.
currency