Hello there!
[tex](First \ step) \\ \\ Factoring: (x2-36) \\ \\ \boxed{ A^2 - B^2 \ can \ be \ factored \ into \ (A+B) * (A-B)} \\ \\\ \left[\begin{array}{ccc}Proof : (A+B) * (A-B) = \\
A2 - AB + BA - B2 = \\
A2 - AB + AB - B2 = \\
A2 - B2\end{array}\right] \\ \\ \\ Factorization is : (x + 6) * (x - 6) \\ \\ \boxed{FINAL \ ANSWER} \\ \\ \boxed{\boxed{ (x + 6) * (x - 6)}}[/tex]
Your correct answer would be (option a) the first option.
I hope this helps you!