Find the Term That Should Be Added to the Expression $x^{2}+18 x+$

Multiple Choice

Find the term that should be added to the expression to form a perfect square trinomial. Write the resulting perfect square trinomial in factored form.
- $x^{2}+18 x+$

A) $81 ;(x-9) ^{2}$
B) $81 ;(x+9) ^{2}$
C) $324 ;(x+18) ^{2}$
D) $0 ;(x+9) \}^{2}$