Factor the Expression That Defines the Function $$n ( t ) = t ^ { 2 } - 18 t + 81$$

Multiple Choice

Factor the expression that defines the function. $$n ( t ) = t ^ { 2 } - 18 t + 81$$

A) $n ( t ) = \left( t - \frac { 9 } { 2 } \right) ^ { 2 }$
B) $n ( t ) = ( t - 9 ) ( t + 9 )$
C) $n ( t ) = ( t - 9 ) ^ { 2 }$
D) $n ( t ) = t ^ { 2 } - 18 t + 81$ (Expression is prime)