Which two statements about the max-age time in IS-IS are true?

Which two statements about the max-age time in IS-IS are true? (Choose two.)

A.
The IS-IS max-age time is 20 minutes by default.

B.
The IS-IS max-age time is 60 minutes by default.

C.
The IS-IS max-age time increments from zero to max-age.

D.
The IS-IS max-age time decrements from max-age to zero.