Factor the Trinomial Completely $3 x ^ { 2 } - 21 x + 36$

Multiple Choice

Factor the trinomial completely. If the polynomial cannot be factored, write "prime."
- $3 x ^ { 2 } - 21 x + 36$

A) $( x - 3 ) ( 3 x - 12 )$
B) $3 ( x - 12 ) ( x + 1 )$
C) $3 ( x - 3 ) ( x - 4 )$
D) prime