**Core Concept**
The umami taste is one of the five basic tastes, alongside sweet, sour, bitter, and salty. It is mediated by specific receptors on the tongue that respond to the presence of certain amino acids, particularly glutamate.

**Why the Correct Answer is Right**
Glutamic acid, also known as glutamate, is a non-essential amino acid that plays a crucial role in the umami taste pathway. When glutamate binds to the taste receptor T1R1/T1R3 on the surface of taste buds, it activates a signaling cascade that ultimately leads to the perception of umami taste. This is because glutamate is a potent agonist of the umami receptor, which is responsible for detecting the presence of glutamate and other related amino acids in food. The umami taste is often described as savory or meaty, and it is a key component of many foods, including meats, seafood, and vegetables.

**Why Each Wrong Option is Incorrect**
**Option A:** Glucose is a simple sugar that stimulates the sweet taste receptors, not the umami taste receptors.
**Option C:** Quinine is a bitter compound that activates the bitter taste receptors, not the umami taste receptors.
**Option D:** Sodium chloride, or table salt, stimulates the salty taste receptors, not the umami taste receptors.

**Clinical Pearl / High-Yield Fact**
The umami taste is often associated with the presence of glutamate in foods, particularly in meats, seafood, and vegetables. However, it's worth noting that excessive consumption of glutamate can lead to a condition known as umami taste fatigue, where the taste buds become desensitized to the umami taste.

**✓ Correct Answer: B. Glutamic acid**