Final answer:
To determine if a number is a multiple of a square number, check if it can be divided evenly by the square number.
Step-by-step explanation:
To determine if a number is a multiple of a square number, we need to check if it can be divided evenly by the square number. Since the question states that the number has a nine in its ones place, the only option that satisfies this condition is A: 9. However, to establish if 9 is a multiple of a square number, we need to check if it can be divided evenly. In this case, 9 can be divided by 3, which is a square number (3^2 = 9). Therefore, the correct answer is B: 3.
Learn more about Multiples of square numbers