The spinal cord ends at the level of L1/L2 where it becomes the:

The correct response is that the spinal cord ends at the level of the first or second lumbar vertebra (L1/L2) and transitions into a structure known as the Cauda Equina. The Cauda Equina, which translates to "horse's tail," is a bundle of spinal nerves and spinal nerve roots that extend downward from the end of the spinal cord. This is important for the innervation of the lower limbs and pelvic organs, as the spinal cord does not extend all the way down the vertebral column but rather terminates, with the remaining nerves extending like a tail.

In contrast to the options that were not selected, they do not represent recognized anatomical structures associated with the termination of the spinal cord. The terms Columna Nidbela, Cassius Labida, and Crassius Ceasarum are not anatomically relevant and do not pertain to spinal anatomy or the transition of the spinal cord into the Cauda Equina. Understanding the correct terminology and the anatomical relationships within the spine is crucial for those studying chiropractic care and related fields.