Answer:
D. (4x - 1)(4x + 1)
Step-by-step explanation:
16 is a perfect square, with its two identical factors being 4. 1 is also a perfect square, with its two factors being 1, but in this case, it's a -1, so we need a positive 1 and a negative 1:
(4x + 1) (4x - 1)
