Regarding fixation of seniority in direct recruitment

Four persons were selected for 4 vacancies. One for General Category, 2 for OBC Category, 1 for Ex-serviceman category. Person "A" in general category got highest marks 79 in test & interviews, in OBC category person "B" got 75.4 and person "C" got 75.6, whereas, in ex-serviceman category person "D" got 72 marks were highest. Now when the selection committee prepared minutes of interview it was written that "the committee after considering the marks obtained in written test and interview recommends the following persons for appointment in the payscale of ----------" 1. A : Gen. Cat. 2. C: OBC Cat. 3. B: OBC Cat. 4. D: Ex-Ser. Cat. Now, the question is that how the seniority will be fixed, i.e. in order the persons got marks or in order the committee recommended their names irrespective of their marks, as C is placed at no.2 instead of No.3 and B at No.3 instead of no.2. All the persons joined their duties on same date and time. Even appointment letters to all the persons were issued in order the selection committee recommended their names in minutes.