Actually, they haven't passed already. There are in total four practical papers and as far as I know, 33 has it's Physics today and 34 is yet to test for all exams.
I'm not referring to a particular practical question, but the rules for choosing an indicator are:
1) If the titration is between a weak base and strong acid, use methyl-orange/screened methyl-orange indicator.
2) If the titration if between a strong base and weak acid, use phenolphthalein indicator.
3) If the titration is between a strong base and strong acid, you can use either indicator.
I'm not sure for a weak base and weak acid, but I believe that is beyond the scope of our practicals.