Asocial scientist conducts a study with 10 subjects. in which situations is a permutation necessary to determine the number of possible outcomes ?
select all that apply
a) schedule interviews for all 10 subjects
b) invite 3 subjects to participate in a repeat study
c) select 3 out of 6 sandwiches and 2 out of 4 desserts for the subjects lunches
d) create a seating chart for 10 subjects around a table
e) administer a survey to 6 of the subjects