Which example correctly demonstrates polynomial addition?(1 point)

To determine which example correctly demonstrates polynomial addition, we need to perform the addition of the polynomials on the left side of the equation for each option.

Let's evaluate each option:

### A)
\[
(2x^2 + 6x + 1) + (3x^2 + 3x + 9)
\]
Combine like terms:
- \(2x^2 + 3x^2 = 5x^2\)
- \(6x + 3x = 9x\)
- \(1 + 9 = 10\)

So, this becomes:
\[
5x^2 + 9x + 10
\]
**This is NOT correct because it equals \(5x^2 + 9x + 10\), not \(-x^2 + 3x - 8\).**

### B)
We already calculated the sum in option A, which is \(5x^2 + 9x + 10\).
- This option states \(13x^2 + 9x + 10\).
- This is NOT correct.

### C)
This option also stated:
\[
(2x^2 + 6x + 1) + (3x^2 + 3x + 9) = 5x^2 + 9x + 10
\]
- This one matches our calculation! **This is correct.**

### D)
This option states:
\[
5x^4 + 9x^2 + 10
\]
However, there is no \(x^4\) term in our original polynomials, which makes this option incorrect.

### Conclusion:
The correct response demonstrating polynomial addition is:

**C) (2x^2 + 6x + 1) + (3x^2 + 3x + 9) = 5x^2 + 9x + 10**.