**Core Concept**
Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) characterized by the accumulation of immature granulocytes, known as promyelocytes. APL is associated with a specific chromosomal translocation, t(15;17), which leads to the fusion of the PML gene with the RARα gene.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of APL. APL is characterized by the accumulation of promyelocytes, which are unable to mature into functional neutrophils due to the PML-RARα fusion protein. This fusion protein interferes with normal granulopoiesis, leading to the accumulation of immature cells in the bone marrow. The PML-RARα protein also promotes apoptosis resistance, which further contributes to the leukemic phenotype.

**Why Each Wrong Option is Incorrect**
**Option A:** APL is associated with a specific chromosomal translocation, t(8;21), which leads to the fusion of the ETO gene with the AML1 gene. This is incorrect because t(8;21) is associated with a different subtype of AML, known as AML-M2.
**Option B:** APL is characterized by the accumulation of lymphoblasts. This is incorrect because APL is characterized by the accumulation of promyelocytes, not lymphoblasts.
**Option C:** APL is associated with a specific chromosomal translocation, t(15;17), which leads to the fusion of the PML gene with the BCR gene. This is incorrect because the BCR gene is involved in chronic myeloid leukemia (CML), not APL.

**Clinical Pearl / High-Yield Fact**
APL is a unique subtype of APL that responds well to all-trans retinoic acid (ATRA) therapy, which induces differentiation of the leukemic promyelocytes. ATRA therapy has revolutionized the treatment of APL and has improved survival rates for patients with this disease.

**Correct Answer:** C.