The normal life expectancy for 50% of patients ith amyotropic lateral sclerosis (ALS) is:
Correct Answer: A
Rationale: Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a progressive and fatal neurodegenerative disease that affects the nerve cells in the brain and spinal cord. The average life expectancy for individuals with ALS is around 2 to 5 years from the time of diagnosis. Therefore, the normal life expectancy for 50% of patients with ALS would be closer to the midpoint of this range, which is approximately 3 years. While some individuals may live longer than 3 years with ALS, for 50% of patients, this would be a reasonable estimate based on the typical progression of the disease.