LONDON: The chief executive of Marks & Spencer said on Wednesday he could not comment on whether the retailer had paid a ransom in a cyber attack which has cost it about 300 million pounds ($402.39 million) and which he said was the result of "human error". ($1 = 0.7455 pounds) (Reporting by James Davey and Paul Sandle, writing by Sarah Young, editing by Catarina Demony)