Puzzle of the week #340

White to move is down a Rook and two pawns. Your tasks:
a) What is the main threat in this position?
b) What should white look for right now and why?
c) Find the best line for white in this position
Total available points for this puzzle is 20. The answers will be published next time together with puzzle #341.

Puzzle #339 solution:
Internet puzzle, 2018. This week's best answers are by the top scorers who did not forget to analyse the position before answering the questions:
Material is equal. Both sides have castled and white has breathing room on "h2". The white pieces are more active (in or closer to the center)
b) White uses a fork and a discovered check/ attack
c) White's pieces were in attacking positions, ready to bring white material advantage after using the right tactics
[Event "Puzzle #339"][Date "2018.03.11"][Result "1-0"][SetUp "1"][FEN "1r3rk1/1pq1nppp/p1n1p3/4N3/8/2PB3P/PP2QPP1/3R1RK1 w - - 0 1"]1. Nd7 Nd5 (1... Qxd7 2. Bxh7 Kxh7 3. Rxd7 {White is up a Queen and pawn for Bishop and Knight}) 2. Nxf8 Kxf8 {White is up a Rook for a Knight}

Correct solutions:
Joey, Itamar, Matthew - 25 points
Lyvia, Aiden, Mengbai, Walter, Eric - 20 points
Coby - 15 points
Glyn - 11 points
Brian, Zhengyu - 8 points
Lucas, Chris - 5 points
Blake - 3 points

Standings:
Matthew - 170 points
Eric - 160 points
Lyvia - 148 points
Coby - 136 points
Joey - 132 points
Aiden - 126 points
Mengbai - 125 points
Glyn - 108 points
Zhengyu - 96 points
Itamar - 89 points
Walter - 85 points
Blake - 81 points
Brian - 80 points
Jacey - 72 points
Lucas - 69 points
Chris - 23 points
Darius - 20 points