You chose to bid 4 Spades. This is the correct answer. Once you realised that you and your partner have an 8 card fit in Spades, you can add 3 extra points to your hand for your singleton. This brings your points to 17, and you can assume your partner has at least 10 from the bidding, so I think a game is certainly worth trying.

After your bid, everyone has a further chance of speaking.

Let's look at West's hand and see if you think there is anything he might want to say at this stage.

Spades         K,10,9,6
Hearts          A,J,5,4
Diamonds     6,5,4
Clubs           A,9

This hand has consistently No Bid on each occasion so far. However, it is a rather nice hand. When the opening bid of 1 Heart was made, West couldn't bid 1 Spade, because that would have promised 5 Spades, and couldn't say 1 No Trump as it doesn't have 16 points, and couldn't say Double (Takeout Double) because that says you have something in everything except the bid suit. So since there was not an honest bid, he chose to No Bid. But when the bidding progressed, the potential of getting the opposition down must become much more obvious. The bid at the moment is 4 Spades. With this hand, you should win the King of Spades, the Ace of Clubs and the Ace of Hearts. If you could also win another trick, you can get the contract down. I think it is worth a DOUBLE.  This is a penalty double, not a takeout double. You are challenging the opposition. Normally you don't double below game level, because if the bid is made, you have doubled their score and put them into a game, which they would not have had. But in this instance, a game is already bid. If they make the contract, they will get 240 points + a 50 bonus for the insult, which would be an extra 170 points for them.  If you get them down 1, Doubled and Vulnerable, you will get a bonus of 200 points, and if you get them down 2, it would be 500 points.  It is a justified gamble.

A Double counts the same as a bid, in that there need to be 3 No Bids after it for the bidding to cease, and if North and South are very confident of their bids, they have the option of REDOUBLING. But in this case, they will be a little bit unsure of themselves, and the best option is to say No Bid. There is always the option of course, of going into another contract, and the other possible bid in this set of hands is in No Trump, but West would no doubt Double 4 No Trump too, so it would not help matters. So South indicates that he is CONTENT, with leaving the contract as 4 Spades, Doubled.

However, the Spades were first bid by North, so North has to be declarer.

The opening lead is important, but with East's hand I think it is better to make a passive lead, rather than playing all the high cards straight off. A PASSIVE lead is one where you don't expect to win - but just use it to start the play off, in contrast to an ACTIVE lead, where you are definately setting up tricks for yourself or your partner straight away.

Spades         5
Hearts         Q,6,2
Diamonds    10,9,7,2
Clubs           J,6,5,3,2

34. Which card would make the best passive lead?

a. 2 of Clubs
b. 2 of Diamonds
c. 2 of Hearts