@FyM020 If we are talking about queen to b3 that is an attack on b7 pawn and forms a battery with its bishop on the e6 pawn. If there was no white bishop on c4 then the tactic would be called a Double Attack.
So white is threatening to either take the b7 pawn or recapture the e6 pawn with it's queen, although not advisable.
What can black do besides moving the knight? What about Rb8?
Black is not forced to move the knight.
But once it did move the knight, then white can always capture the black pawn with bishop check and that forces the king to move or recapture with the rook and be down material because white would recapture with its queen with tempo and the knight would be on the rim
Or the knight can just capture the bishop instead of queen and material remains even as well.
The confusion is with the definition of "tactic".
A tactic is a forcing move or combination of moves that lead to an immediate advantage of material or a mating pattern. Generally there is just some kind of imbalance that will lead to a win with best play.
Many people, are confused by semantics and some even think there is a difference between tactics and combinations. They seem to think a combination has to have a sacrifice. It's not necessary.
Realize there are only 5 basic families of tactics which was addressed in #3 and everything is a combination of these.
Removing the Guard is a broad category including , Capturing the Guard, Distracting the Guard, Attacking the Guard or Blocking the Guard. Many authors have their own names for things. For example, 'interference", is another way of saying, "blocking the guard".
Hope this is helpful.