**Core Concept**
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the loss of motor neurons in the spinal cord, brainstem, and motor cortex. The primary goal of treatment is to slow disease progression and manage symptoms.

**Why the Correct Answer is Right**
Riluzole, a drug found beneficial in ALS, acts by inhibiting the release of glutamate, a neurotransmitter that can be excitotoxic to motor neurons. By reducing glutamate levels, riluzole may help slow disease progression. This mechanism is thought to be beneficial in ALS, although the exact pathophysiology of the disease remains poorly understood.

**Why Each Wrong Option is Incorrect**
**Option A:** Edaravone is an antioxidant that has been shown to slow disease progression in ALS, but it is not the first-line treatment.
**Option B:** Baclofen is a muscle relaxant used to manage spasticity in ALS, but it does not slow disease progression.
**Option C:** Tizanidine is another muscle relaxant used to manage spasticity in ALS, but it also does not slow disease progression.

**Clinical Pearl / High-Yield Fact**
Riluzole is the only FDA-approved medication for the treatment of ALS, and it has been shown to prolong survival by an average of 2-3 months.

**Correct Answer:** C.