Hello there. To solve this question, we have to remember some properties about roots of polynomials.
Given the following function:

We want to determine its roots.
For this, we want to determine the values of x such that

Then we have that

We know that a product of two values is equal to zero if and only if one of them is equal to zero.
So we have that

Subtract 6 on both sides of the first equation, we get

Divide both sides of the equation by a factor of 2

Now for the second equation, add 4 on both sides of the equation

Hence we say that the roots of this function are

This is the answer contained in the last option.