Look at the responses to the questions asked. This will help you decide what question is being asked. Also, checking each question word to see which one matches best is also a good way.
For number 1 it would be Qui
He is asking who your best friend is.
For number 2 it would be Comment
He is asking how Gabriel is, as in what he is like.
For number 3 it would be Qu'
He is asking what you like to do for fun.
For number 4 it would be Avec qui
He is asking with whom you play tennis with.
For number 5 it would be Quand
He is asking when you play tennis.
For number 6 it would be Où
He is asking where you play tennis.
For number 7 it would be Pourquoi
He is asking why you like maths.
If you have any further questions feel free to ask.
Hope this helps!
