Anyway interview is over now. By chance if the milk is spilt, then there is no point in crying over it now. Against this backdrop, search on the net and find out what is employee engagement. Find out who has done study on employee engagement activities. Find out whether anybody has measured ROI on engagement activities. Make your reply and post it here. Ask seniors to evaluate your reply.
Lot of material is available on this forum on employee engagement. However, recommending to you something from some other website or from this forum would be spoon feeding. Leave aside of spoon feeding, one cannot grow even with spade feeding. Therefore, take interview as lesson, work on your own and then ask for the feedback.
All the best!