Concept:Identify which number does not follow the common property of being a perfect square.
Explanation:Examine each option to see if it is a perfect square.
121 equals 11 × 11, so it is a perfect square.
169 equals 13 × 13, so it is a perfect square.
144 equals 12 × 12, so it is a perfect square.
189 cannot be expressed as any integer multiplied by itself.
Therefore, 189 is the only number that is not a perfect square.
Answer:Option B (189)