Shakespeare's pacing and action became more immediate and tense when he shortened the timeframe of the play to 4 days shortened the timeframe of the play to 2 weeks lengthened the timeframe of the play to several months left the timeframe the same as brooke’s version

The answer would be shortened the time frame of the play to four days. It is because Shakesphere has the idea or thought of shortening the time frame in which it is not longer than weeks or months but days. This will allow audiences to stir up their mood in a way the tension will be quicken, in order to make a better play and good finish. This allows Shakesphere's action became tense as the time frame quickens, the play is about to end.