Explanation:

Let’s break it down:

- If two numbers are co-prime, their greatest common divisor (GCD) is 1.

- When you multiply two co-prime numbers, the least common multiple (LCM) is just their product.

- Here, their product is 117.

- So, their LCM must also be 117.

Let’s look at the options:

1. 117 – That’s the product, so yes, that’s the LCM.

2. 9 – Just one possible factor of 117; doesn’t fit.

3. 13 – Another factor, but not the LCM.

4. 39 – A factor too, but not the LCM of two co-prime numbers whose product is 117.

So, the right answer is Option 1: 117.