Answer: The correct option is third, i.e., .
Explanation:
The given function is,
The Rational Root Theorem states that the rational roots are in the form of,
These rational roots are possible rational roots not the actual roots of f(x).
For actual roots of f(x), the value of the function is 0.
Put each value of x from the option in the function, if we get the value of f(x) is 0, then that value is the actual root of f(x).
Put x=3.
Put x=6
Put
Put
Only for the value of function is 0, therefore the correct option is third.