Atrophy of the intrinsic muscles of the right arm and forearm. Reflexes are generally brisk, plantar reflexes are extensor. Electrophysiology shows widespread fasciculations, fibrillation, and sharp waves. What is the diagnosis?
A) Myasthenia gravis
B) ALS (Amyotrophic lateral sclerosis)
C) Guillain-Barré syndrome
D) Multiple sclerosis