Find the Term That Should Be Added to the Expression $x^{2}-16 x$

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.
- $x^{2}-16 x$

A) $64 ;(x+8) ^{2}$
B) $64 ;(x-16) ^{2}$
C) 0 ; $(x-8) ^{2}$
D) $64 ;(x-8) ^{2}$