B
ridge On One PageReply to 2 No Trumps - 0 to 4 Points
After your partner has done an opening bid of 2 No Trumps, your bid then depends on your reply points. If the value of your hand is 4 points or less, you must always bid, as the 2 level opener is 'forcing'. The standard bid here is 3 Diamonds, known as the Flint Convention, as it is simply an indicator of your points, and it is possible you could even have a void in diamonds !
Example
Here you have no points, or arguably 1 point for a doubleton. A hand of zero value is called a 'Yarborough' ! So your bid is 3 Diamonds. This does not mean that your longest suit is diamonds, although it happens to be in this example.
Note
A cautious player might decide to pass on a Yarborough, but in so doing he or she may miss the opportunity of getting a game. Generally speaking, the scoring system for rubber bridge is such that it favours more adventurous players.