The correct option is D Delay
The given word 'postpone' means to cause something to happen at a time later than expected, for example, 'The flight got postponed by an hour.'.
We need to choose a synonym for this word: a synonym is a word that is similar in meaning to another.
From the options, 'delay' means to make something late, for example, 'the flight got delayed by an hour.'.
These two examples mean the same thing, hence 'delay' is the synonym here and option A is correct.
'Deliver' means to hand over or bring something to someone. It has no connection to 'postpone'.
'Forward' means 'moving ahead, moving in front', it isn't the same meaning as the given word.
'Hurry' means to move or act in a haste. it is opposite in meaning to the given word.
Hence options B, C, and D are incorrect.