You need to post the entire context. Probably 'development of the park' will turn out to be correct, because it seems preferable in terms of the meaning and sounds smoother, but the key issue in this one is the modifier that comes after the phrase.

kalyand022 wrote:park's development or development of the park...

i m confused of ths trick in sentence correction.i hv my exam ths week..so pl enlighten on ths topic

Both can be correct, the error can be somewhere else. Please post the whole sentence.

The development of the park was one of the issues faced by the government

The parks development was one of the issues faced by the government

I believe the correct answer is going to be "the development of the park." But it's hair-splitting, and I'm not sure the real GMAT would have a question that rests on such a tiny difference. It's a very tricky issue -- professional linguists who have studied the question of when native speakers prefer the possessive construction or the 'of' construction have never fully pinned down the answer, so far as I know, though some patterns have been identified.

I'm very curious as to where this item came from, and whether the people providing it claimed that there was a clear-cut rule that would explain why one is preferable to the other.

kalyand022 wrote:The development of the park was one of the issues faced by the government

The parks development was one of the issues faced by the government

You should post entire question along with the options given; preferably with the source of the question.

Thank you.