Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:When they finished playing the game, the participants were asked to complete a post-knowledge acquisition questionnaire, a 15-question AGT survey (Elliot & McGregor, 2001) and an 11-question player type survey (Foster, 2011).
Category: