**Core Concept**
The question is testing the understanding of alpha-thalassemia, a genetic disorder caused by mutations in the alpha-globin gene. Alpha-thalassemia is characterized by reduced production of the alpha-globin chains of hemoglobin, leading to various clinical manifestations.

**Why the Correct Answer is Right**
Deletion of one alpha-globin gene on one chromosome is known as alpha-thalassemia trait (also known as alpha-thalassemia carrier state). This condition occurs when one of the four alpha-globin genes is deleted, resulting in a mild reduction in alpha-globin production. The unaffected alpha-globin genes compensate for the deleted gene, minimizing the clinical impact. The alpha-globin genes are located on chromosomes 16 (two genes) and 4 (two genes).

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we can't explain why it's incorrect.
* **Option B:** This option is not provided, so we can't explain why it's incorrect.
* **Option C:** This option is not provided, so we can't explain why it's incorrect.
* **Option D:** This option is not provided, so we can't explain why it's incorrect.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the severity of alpha-thalassemia depends on the number of deleted alpha-globin genes. Deletion of two genes (one on each chromosome pair) leads to alpha-thalassemia trait, while deletion of three or four genes results in more severe forms of the disease.

**Correct Answer: A. Alpha-thalassemia trait**