These are all wrong. You do a correct push-up by lowering you body while keeping your back as straight as possible and lower until your nose almost touches the ground. For a more experienced body builder like myself, I go down and stay at the same level for about 15 seconds and repeat about 30 times. When doing push-ups, your knees should never be touching the ground and this is for everybody. What people call "girl" push-ups just makes me laugh. You don't gain any work from doing that!
