Take context from the input text and decide on the accurate relationship between 'Sabadell' and 'euro' from the options provided.
Options: distribution format, industry, chief executive officer, currency

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