Which activities may lead to alpha-numeric document numbers?

You notice alpha-numeric document numbers in the Universal journal that do not have a separate document header stored in the BKPF table.

Which activities may lead to alpha-numeric document numbers?

There are 2 correct answer to this question.
A . Balance carry forward
B . Corrections due to migration
C . Settlement of investment orders
D . Cross company code postings

Answer: C,D