which activity is the sequence of numbers 0, 1, 2, 3, 5, 8, 13 often used?

During which activity is the sequence of numbers 0, 1, 2, 3, 5, 8, 13 often used?

A.
Estimating points of a story

B.
Denoting development sequence

C.
Estimating development hours

D.
Indicating priority of a story