Read the passage given below and solve the questions based on it.
Mr Bose can do a job in two days if his four secretaries A, B, C and D are all present. His efficiency got reduced to respectively as A, B, C and D remain absent. In any day only one secretary remains absent. Also Mr Bose finishes his work exactly in integral number of days.
If Mr Bose finished his work in 6 days with one secretary being present every day, then the secretary was