The product of the multiplication problem is \( \sqrt{225} \).
Calculating the square root, we have:
\[ \sqrt{225} = 15 \]
Since 15 is a rational number, we can deduce the nature of the factors involved in the multiplication that yields this product.
For any two numbers \( a \) and \( b \) such that \( a \cdot b = 15 \):
- If both factors \( a \) and \( b \) were irrational, their product would also be irrational.
- If both factors were rational, their product would also be rational.
- If one factor is rational and the other is irrational, the product would be irrational as well.
Since the product \( 15 \) is rational, both factors must be rational or at least one must be rational. Therefore, the correct answer among your options is that:
They are both rational because the product is rational.