Which two spinal curvatures are obvious at birth?

The two curvatures that are obvious since birth are the thoracic curvature and sacral curvatures. These are the curvatures that, still through the adult life, are present since birth. These are the anteriorly concave curvatures of the spine. When at birth all spine has a concave curvature that is lost in some parts due to the biped position and head sustaining.

C- a hypothesis or d- an observation