Answer:
Option A is correct.
the root of the given function is, {2, 6}
Explanation:
Given the function:

To find the root of the given function;
Set f(x) = 0
⇒
In the Quadratic Factorization using Splitting of Middle Term which is x term is the sum of two factors and product equal to last term.
Step 1. Find the product of 1st term and the last.
Product =

Step 2. Find the factors of 12 in such way that addition or subtraction of that factors is the middle term, i.e -8x(Splitting of middle term)
Factor =

Therefore, -6-2= -8
Step 3. Group the terms to form pairs:
(x-6)(x-2) = 0
By zero product property ; we have
⇒x -6 = 0 and x -2 = 0
⇒x =6 and x = 2
Therefore, the roots of the function
is, 2 and 6