Find the Value of K So That the Expression Is $$y ^ { 2 } - 8 y + k$$

Multiple Choice

Find the value of k so that the expression is a perfect square trinomial and then factor the trinomial. $$y ^ { 2 } - 8 y + k$$

A) $k = 16 ; ( y - 4 )$
B) $k = 4 ; ( y - 4 ) ^ { 2 }$
C) $k = 4 ; ( y + 4 ) ^ { 2 }$
D) $k = 16 ; ( y - 4 ) ^ { 2 }$