This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
All are true about subacute combined degeneration of spinal cord except : 
Select and explain. 
A. Due to deficiency of vitamin B12, B. Posterior column involvement, C. Coicospinal involvement, D. Absent deep tendon reflexes
D: Absent deep tendon reflexes
Answer: D: Absent deep tendon reflexes 
Explanation: Answer is D (Absent deep tendon reflexes): Subacute Combined Degeneration Of Cord is a condition of the spinal cord characterized by demyelination of its neurons due to deficiency of Vit B12 which results in defective/ deficient myelination. Such demyelination occurs predominantly in - Posterior column of spinal cord - Pyramidal tract of spinal cord Subacute Combined Degeneration Of Cord is characterized by involvement of: Posterior column of lower cervical & upper thoracic region This is where changes commence. Paraesthaesias, consisting of tingling & numbness and that of pins & needles Q * Loss of vibration sense Q * Position sense is involved to a lesser extent. Q * Ataxic gait Lateral columns (coicospinal tracts) Their involvement follows the involvement of post columns. Motor defects such as weakness and spasticity Q Increased deep tendon reflexes, clonusQ Plantar extensor Q Spastic gait (Note that gait is initially ataxic but later becomes both spastic and ataxic. Q(at an early stage patellar & achilles reflexes may be diminished, increased or absent).