Which free form text fields within a step can be configured with variables?

you want to make a dynamic PDI transformation that is driven with variables that areloaded from a properties file.

Which free form text fields within a step can be configured with variables?
A . Any free form text field with a ”V” next to it
B . any free form text field with a ‘@’ sign next to it.
C . any free form text field with a ‘$’ sign next to it.
D . Any free form text field with the variable name entered in all caps

Answer: B