A newborn presents with a sac-like protrusion in the lumbosacral region containing CSF and neural tissue. This condition is best described as:

Correct option is C

Myelomeningocele is the most severe form of spina bifida where both meninges and spinal cord tissue herniate through a defect in the vertebral arches.
Explanation of options: (a) ✘ Spina bifida occulta shows only bony defect with tuft of hair, no sac. (b) ✘ Meningocele contains CSF sac but no neural tissue. (c) ✔ Correct; myelomeningocele has both fluid and neural elements protruding. (d) ✘ Encephalocele involves cranial defect with brain tissue protrusion, not spinal.