Factor the Expression Completely $$36 z ^ { 2 } + 84 z + 49$$

Multiple Choice

Factor the expression completely. $$36 z ^ { 2 } + 84 z + 49$$

A) $\quad ( 6 z + 7 ) ^ { 2 }$
B) $\quad ( 6 z - 7 ) ^ { 2 }$
C) $\quad ( 6 z + 7 ) ( 6 z - 7 )$
D) $\quad 7 ( 6 z + 7 )$