In an ODI interface, is it mandatory to use a join to describe a lookup?

In an ODI interface, is it mandatory to use a join to describe a lookup?

A.
Yes, it is not possible to set anything other than a join in an ODI Interface.

B.
No, there is a graphical object dedicated to set a lookup in the source area of an
interface.

C.
Yes,there are not many other graphical Objects to describe a lookup.

D.
No,you can use variables in ODIto declare lookups.