This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
Which of the following is involved in amyotrophic lateral sclerosis? 
Select and explain. 
A. Raphae nucleus, B. Lower motor neuron, C. Posterior column, D. Anterior and posterior column
B: Lower motor neuron
Answer: B: Lower motor neuron 
Explanation: Ans. B. Lower motor neurona. Amyotrophic lateral sclerosis is the most common form of progressive motor neuron disease.b. The pathology of motor neuron degenerative disorders involves lower motor neurons (consisting of anterior horn cells in spinal cord and their brainstem homologues innervating bulbar muscles) and upper or corticospinal motor neurons (emanating from layer 5 of motor cortex to descend via the pyramidal tract to synapse with lower motor neurons, either directly or indirectly via interneurons).