Hi @ArunimaSri ,
The first model's right eye is not open while the left is. In addition, it's not correctly rendered.

In addition to the right side being inconsistently out of focus and the section at the waist being too blur, there is an error there with the rendering. The right hand has a problem.

Overall, I'd say that the first file is of poor quality. The more I zoom in on the image, the more the quality fades. A buyer cannot crop the subject from the background, neither can he re-size it to use on a large canvas.
The second image has invisible margin.

There is an issue with the rendering of the eye.

The lips too has an invisible margin and are looking strange. The nose has red around the edge and also in the eye.

There is an error with the edge of the third model's dress shoulder.

The eye lashes are clumped together and what appears to be an indent in the eyelid.

This too, the quality fades as I zoom in.
Best wishes
Jacquelin