Explanation

"Play being recognized" as an important factor in improving mental and physical health and thereby reducing human misery and poverty.

• eliminates an error in the sentence

"Play is recognized as" an important factor in improving mental and physical health and thereby reducing human misery and poverty.

"کھیل کو" ذہنی اور جسمانی صحت کو بہتر بنانے اور اس طرح انسانی مصائب اور غربت کو کم کرنے میں ایک اہم عنصر کے طور پر تسلیم کیا جاتا ہے۔
...

• Error in following conventions.
• This is an incomplete sentence or fragment.
• The sentence needs a verb to establish a principal clause.
• Choice D provides the verb (is recognized) and presents the only complete sentence in the group.