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: Radiology
A middle aged man presents with progressive atrophy & weakness of hand & forearms. On examination he is found to have slight spasticity of the leg, genera-lized hyperreflexia and increased signal in the coico-spinal tracts on T2 weighted MRI. The most likely diagnosis is: 
Select and explain. 
A. Multiple Sclerosis, B. Amyotrophic lateral sclerosis, C. Subacute combined degeneration, D. Progressive spinal muscular atrophy
B: Amyotrophic lateral sclerosis
Answer: B: Amyotrophic lateral sclerosis 
Explanation: B i.e., Amyotrophic Lateral Sclerosis The presence of both lower motor neuron signs (progressive atrophy & weakness of hands) and upper motor neuron signs (spasticity & hyperreflexia) in the patient with increased signals (hyperintensity) of coicospinal tracts on T2WI of MRIQ leads us to the diagnosis of Amyotrophic lateral sclerosis.