**Core Concept**
Reticulocytosis is an increase in the number of reticulocytes (immature red blood cells) in the peripheral blood, often indicative of bone marrow response to anemia or erythropoietin stimulation.

**Why the Correct Answer is Right**
Reticulocytosis is typically seen in conditions where there is an increased demand for red blood cells, such as hemolytic anemia, blood loss, or erythropoietin therapy. The bone marrow responds by increasing red blood cell production, leading to an increase in reticulocytes in the peripheral blood.

**Why Each Wrong Option is Incorrect**
**Option A:** Reticulocytosis is indeed a feature of anemia of chronic disease, as the bone marrow attempts to compensate for the lack of erythropoietin stimulation. This makes A incorrect.
**Option B:** In aplastic anemia, the bone marrow fails to produce sufficient red blood cells, leading to pancytopenia, including a decrease in reticulocytes. This makes B incorrect.
**Option C:** In chronic kidney disease, erythropoietin production is impaired, leading to anemia. However, reticulocytosis can occur if erythropoietin therapy is administered. This makes C incorrect.

**Clinical Pearl / High-Yield Fact**
Reticulocytosis is a dynamic indicator of bone marrow response and can be used to monitor the effectiveness of anemia treatment.

**Correct Answer: B.**