Do you mean an extraneous solution? I will tell you what I think. To tell if a solution is extraneous you need to go back to the original problem and check if there actually is a solution or if the solution is actually right. If not then it is extraneous.
I believe the answer is A because its the only one that makes the most sense.
In elementary algebra, a trinomial is a polynomial consisting of three terms or monomials.
