Chess Puzzle of the Week (105)

A similar question to last week.

It often happens that you play Bg5 to pin an enemy knight on f6. Your opponent, not liking the pin, tries to drive it back with h6 and g5. You then have a choice: do you prefer a quiet retreat to g3 or do you boldly sacrifice a piece for two pawns? And, if so, do you sacrifice your bishop or your knight?

In this game White, having played a thematic pawn sacrifice (d6) in the opening, is now faced with precisely this decision.

What would you advise?