Final answer:
By adding p (-9) and q (4) together, we get r = -5, which means the statement A. r = -5 is true.
Step-by-step explanation:
If p = -9, q = 4, and p + q = r, we can calculate the value of r by simply adding the values of p and q together. So, r is equal to -9 + 4.
Let's do the math:
Therefore, the statement about r which is true is A. r = -5.