Final answer:
The error in TROY's factoring is incorrect sign in the factors. Factors of a trinomial should have opposite signs to maintain the middle term's sign. Hence the correct answer is option C
Step-by-step explanation:
The error in TROY's factoring is Incorrect sign in the factors.
Factors of a trinomial should have opposite signs to maintain the middle term's sign. If we have a positive middle term, one factor should be positive and the other should be negative, and vice versa. However, TROY might have made a mistake and factored the trinomial with incorrect signs in the factors.
For example, let's consider the trinomial 2x^2 - 5x + 3. The correct factoring would be (2x - 1)(x - 3), where the signs in the factors are opposite. If there were an error in the factoring, it could be (2x + 1)(x + 3), which has the incorrect signs.
Hence the correct answer is option C