Puzzle of the week #278

Chess Diagram: 

[Event "Puzzle #278"][Date "2015.05.19"][Result "1-0"][SetUp "1"][FEN "3Q4/4R2p/1pq2p1k/6p1/8/6PP/1rp2P1K/8 b - - 0 1"]

This is an extremely sharp position with black to move: white threatens to checkmate, while black threatens to promote the c2-pawn and go up in material. Your tasks:
a) Show how white would checkmate if it could be its turn to move
b) Analyse the position and decide which side has a more powerful threat
c) Find the best line black should play now

Total available points for this puzzle is 25. The answers will be published next time together with puzzle #279.

Puzzle #277 solution:
Game Ferarini – Moresi, Italy 1972. Coco provided the best answer of the week and possibly of the year:
"a) White should play ahead because in chess games:
1. You never know if the opponent will blunder. Take the chance and sacrifice at the cost of drawing or winning!
2. White has the privilege to move first and also has many useful pieces that can begin an attack ( queen, bishops, rooks etc.), while black has a lack defending (too focused on attack)
3. Black's king is also in the corner like white's

[Event "Puzzle #277"][Date "2015.05.05"][Result "1-0"][SetUp "1"][FEN "k1r1r3/p5p1/1b1Q4/nN2B3/4p3/1B3pPq/1P3P1P/R4R1K w - - 0 1"]1.Bd5+ {Checks the Black king so it is forced to be block. Delays Black's mate} 1...Nb7 {Blocks king from bishop the safer way} (1...Nc6 2.Bxc6+ Rxc6 3.Qxc6#) 2.Qb8+ {Sacrifices queen for a Smothered mate} 2...Rxb8 3.Rxa7+ {A check to lure the defending bishop away followed by forced move} 3...Bxa7 4.Nc7#

Correct solutions:
Coco - 20 + 5 (bonus)
Bradley, Cody - 20 points
Aaron - 12 points
Deryk, Benjamin, Terry - 10 points
Yakov, Hyson - 5 points
Uros - 1 point

Coco - 213 points
Bradley - 185 points
Cody - 183 points
Benjamin - 162 points
Jalen - 154 points
Hyson - 150 points
Deryk - 123 points
Aaron - 114 points
Yakov - 107 points
Terry - 79 points
Uros - 26 point
Dheera - 9 points
Andrew - 8 points