Explanation:

Let’s break this down:

- Statement A: Their sum is 16.

- The *smallest* set of five distinct natural numbers that add up to 16 is 1, 2, 3, 4, 6.

- There’s only one way to pick 5 distinct natural numbers (without repeats) to get 16—the lowest possible values force the others up once you set aside 1, 2, 3, 4, and then only 6 fits to keep the sum to 16.

- So you can find the smallest, and it’s 1. (A alone is sufficient).

- Statement B: Their product is 720.

- Here’s the thing: break 720 into 5 factors, all different natural numbers.

- 1 × 2 × 3 × 4 × 5 = 120, which is too low.

- Try 1 × 2 × 3 × 4 × 6 = 144, still too low.

- 2 × 3 × 4 × 5 × 6 = 720, but now 1 is missing. So the sets can vary. The smallest number could be 1 or 2, etc.

- Multiple valid sets, so you *can’t* tell the smallest just from this.

- Option review:

1. Only A is enough; B isn’t.   (This is the right call!)

2. Only B is enough—not true.

3. Need both—not true, since A works alone.

4. Both statements separately work—not true, B fails.

So, don’t second-guess yourself. Statement A locks it in; Statement B leaves things wide open. Option 1 is absolutely the answer.