Chess Puzzle of the Week (115)

Something a bit easier this time.

I currently have an interest in positions – very common in junior games in particular – where there’s an opportunity to sacrifice a minor piece for two pawns on g4/g5 against a castled king.

Sometimes it works, sometimes it doesn’t.

Here’s an example. It’s Black to move here. How would you assess Nxg4?

a) It’s better for Black

b) It’s about equal

c) It’s better for White

Don’t forget to give reasons for your decision!