Explanation:

Alright, let’s break this down step by step:

- We’re given 15 : 135, 16 : ?, and 18 : 189. We need to find what goes with 16.

- Look for a pattern. Take 15 and its pair, 135. 15 × 9 = 135. Simple multiplication.

- Next, 18 : 189. Do the same: 18 × 10.5 = 189? No, that doesn’t fit. Wait—let’s check 18 × 10.5: 18 × 10 = 180, 18 × 0.5 = 9, so 180 + 9 = 189. Yes!

- But the first pair is 15 × 9, the third is 18 × 10.5. See a pattern? Let's see the increment: 9 to 10.5 is an increase of 1.5.

- Let’s check what 16 should be multiplied by to fit the middle of those steps.

- The pattern: 15 × 9, 16 × ?, 18 × 10.5. So for 16, maybe 16 × 9.5?

- 16 × 9.5 = 152.

Here’s what the options look like:

1. 152

2. 121

3. 131

4. 141

- The math lines up with 152. So that’s the answer, and just to be clear, here’s the sequence:

- 15 × 9 = 135

- 16 × 9.5 = 152

- 18 × 10.5 = 189