Farmer Company has no beginning work in process; $9,000$ units are transferred out and $3,000$ units in ending work in process are one$-$third finished as to conversion costs and fully complete as to materials cost. The equivalent number of units with respect to materials are $\_\_\_\_\_.$

Question $2$ options:

A$)$

$3,000$

B$)$

$6,000$

C$)$

$9,000$

D$)$

$12,000$

E$)$

none of the above