Anita was doing a survey in different companies by working on all days of the week. She started with company ‘A’ and on completing her work she went to company ‘B’ on the third day. She was required to work there for three days and then went to company ‘C’ on the fourth day. She worked in company ‘C’ on the fourth day. Thereafter she worked in company ‘D’ and completed her work on fourth day after working for three days which was a Saturday. On which day did she start her work in company A ?