When you read or write to a sequential file, and wish to have a value be identified with DataStage as NULL,
which of the following is the correct option?

A.
Set format’s fill char option using the value

B.
Set string type default option using the value

C.
Set format’s null field value option using the value

D.
Set $APT_IMPEXP_REJECT_NULLS using the value

Explanation:
https://www- 01.ibm.com/support/knowledgecenter/SSZJPZ_11.3.0/com.ibm.swg.im.iis.ds.serverjob.dev.doc/to
pics/r_dsvjbref_Defining_Sequential_File_Output_Data.html