Which among the following is the commonest type of presentation?

Commonly, the head is flexed sharply so that the chin is in contact with the thorax. The occipital fontanel is the presenting pa, and this presentation is referred to as a veex or occiput presentation. Much less commonly, the fetal neck may be sharply extended so that the occiput and back come in contact, and the face is foremost in the bih canal--face presentation. Shoulder and breech presentations are also less common. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 17. Normal Labor and Delivery. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.