Which of the above six measurement method is the most preferred way to you? Why?

Factor Analysis：answer the questions in the ppt

If you want to study the relationship between group helping (altruistic) behaviors within the group and group cohesiveness,
(1) Name two ways you can measure altruistic behaviors by self-report at the individual level? (please write out the item) How would you analyze the data?
(2) Name two ways you can measure altruistic behaviors by other-report at the individual level? (please write out the item) In what way would you collect your data?
(3) Name two ways you can measure altruistic behaviors at the group level.
Which of the above six measurement method is the most preferred way to you? Why?