Explanation

Box 1: No
Example: Greet a user whose name is stored in `user.name`
- ${ welcomeUser(user.name) }
Example: Greet a user whose name you don't know:
- ${ welcomeUser() }
Box 2: No
Greet(User) is a Send a response action.
Box 3: Yes
Reference:
https://docs.microsoft.com/en-us/composer/how-to-ask-for-user-input