Which of the following are TRUE

Which of the following Statements are True

A.Null is only supported default value for LOB(large objects) column in DB2
B.In a JCL job steps,concatenated datasets can exits on different types of devices.
c.A cobol program (say 'pgm1') can be link edited uisng TSO command
'LINK pgm1'.

D.When ever a VSAM record is retrieved from DSAD ,the entire CA containing the record is read into VSAM buffer.

a) C & D
b) B & D
c) A,C & D
d) A,B & D

Option B i.e statement B & D is true and rest are false.