Black’s queen has taken the offensive, attacking your knight on c5. Consider your counterattacking possibilities before resorting to defensive play. A queen sitting as far toward the middle of an open board as Black’s does here should generate thoughts of skewers. This queen in particular is aligned with several of its pieces. What you need is a piece of your own that can attack the queen safely while also aimed through it at a worthwhile target. Bf4 fits the bill: the bishop attacks the queen, and is protected by the rook on f1. Black can use his queen to guard the rook on b8, but that's okay. White still wins the exchange.