White has no queen checks and Black has no loose pieces (except his queen, which generally is not a suitable target for a queen fork). Again, though, it is our practice to examine every check of any sort, and here White has one: BxN, which leads to KxB. All right; now examine the board as it would look after that exchange, and re-ask the important questions: what checks now would be available, and what loose pieces? There are two checks: Qd3 and Qc2. The interesting one is Qd3, because it also attacks the Black bishop on d5. The bishop is protected once, by Black’s queen. But notice that now it would be attacked twice, by the White queen and rook. So Qd3+ wins the bishop after Black’s king retreats.