**Core Concept**
The semi-essential amino acids, also known as conditionally essential amino acids, are a group of amino acids that can be synthesized by the human body under normal conditions but become essential during periods of growth, illness, or stress when the body's demand exceeds its production capacity. These amino acids play a crucial role in various bodily functions, including protein synthesis, neurotransmitter production, and immune response.

**Why the Correct Answer is Right**
The correct answer includes histidine, glutamine, arginine, and tyrosine, which are conditionally essential amino acids. Histidine is crucial for the synthesis of histamine, a neurotransmitter involved in immune responses and allergic reactions. Glutamine serves as a fuel source for enterocytes and is involved in the synthesis of glutathione, a powerful antioxidant. Arginine is essential for the production of nitric oxide, a vasodilator that helps regulate blood pressure. Tyrosine is a precursor for the synthesis of various neurotransmitters, including dopamine, norepinephrine, and epinephrine.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** This option is not provided.
* **Option C:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the classification of amino acids as essential or non-essential can change depending on the individual's nutritional status and health conditions. For example, individuals with impaired gut function or those undergoing prolonged fasting may require semi-essential amino acids to maintain optimal health.

**Correct Answer: C. Histidine, Glutamine, Arginine, and Tyrosine.**