Puzzle of the week #330

Level: 
2-Knight
Chess Diagram: 

[Event "Puzzle #330"][Date "2017.12.10"][Result "1-0"][SetUp "1"][FEN "4r1k1/p1pq1p1p/8/3p4/5Q2/1P3PP1/P1P3KP/4R3 w - - 0 1"]

Black is down a pawn and with his last move (Re8) he wants to trade the Rooks or force Re1 to move away from the e-file. Both options would give him good chances to save the game. Your tasks:
a) White to move and win
b) What is the best choice to respond from the six possible ones with Re1 under attack?

Total available points for this puzzle is 10. The answers will be published next time together with puzzle #331.

Puzzle #329 solution:
Puzzle by John A Bain, 2002. This week's best answers are by Blake:
"After the first move with check white can only capture (choice 1)
After the second move with check white can either move away (choice 2) or block the attack (choice 3)
After the last move with check white must move away"

[Event "Puzzle #329"][Date "2017.12.03"][Result "0-1"][SetUp "1"][FEN "4r3/pp3pkp/2p2np1/5b2/2P1r3/1P4PP/P2N1PB1/R3RK2 b - - 0 1"]1...Rxe1+ 2.Rxe1 Bd3+ 3.Kg1 (3.Re2 Bxe2+) 3...Rxe1+

Correct solutions:
Matthew, Blake, Darius, Coby - 12 points
Lucas, Joey - 10 points
Glyn, Eric - 9 points
Chris - 2 points

Standings:
Matthew - 99 points
Lyvia - 80 points
Coby - 73 points
Eric - 68 points
Glyn - 64 points
Blake - 51 points
Joey - 48 points
Darius - 42 points
Justin, Ellie - 38 points
Zheng Yu - 24 points
Brian - 22 points
Lucas - 21 points
Itamar - 20 points
Jacey - 3 points
Chris - 2 points

Comment: 

Attacks and defences