What GoldenGate facility allows for custom processing in response to a data value?

What GoldenGate facility allows for custom processing in response to a data value?

A.
DDLGEN

B.
GGSExec

C.
User Exits

D.
User Tokens

Explanation:

Reference :
http://download.oracle.com/docs/cd/E15881_01/doc.104/gg_wux_ref_v104.pdf