Elliot has spent the past 12 years of his life as a dedicated stay-at-home dad, helping to raise four kids. His last child, Sabine, has recently left home to join the military, and Elliot is now feeling a sense of despondency and lack of purpose. In this example, Elliot is most likely experiencing what type of crisis?

a) Developmental

b) traumatic event

c) existential

d) psychiatric