For a quadratic equation, the negative of the numerical coefficient of the second term is the sum of the roots and the constant is their product. Let a and b be the roots such that,
a + b = 8
ab = 16
The values of a and b are 4 and 4. Such that the factors are,
(d² - 4)(d² -4)
Both the factors are difference of two squares. The final answer for this item is,
(d + 2)(d - 2)(d + 2)(d - 2)
This is letter D.
