Explanation
For this exercise, you need the following aspects in order to segment your core/saved audience:
1. Age: you definitely want to set up age below 25 years old.
2. Mobile Device User: you need to specify Android as the primary operating system for mobile in order to target just Android users and exclude iOS users.
3. Location: you want to target the specific countries. In this case, Colombia and India in order to reach out to people in those two particular places.

You don't want to use App Store Region as an option to segment as they don't allow you to select specific countries. You are better off selecting countries and Mobile Device User to segment.

The gender and interest for this exercise are irrelevant since you don't have more info on what the mobile app is about.