**Core Concept**
Acute Myeloid Leukemia (AML) is a heterogeneous group of malignant disorders characterized by the clonal expansion of myeloid blasts in the bone marrow. The prognosis of AML varies widely depending on several factors, including the specific genetic and molecular abnormalities present.

**Why the Correct Answer is Right**
The best prognosis in AML is associated with the core binding factor (CBF) leukemias, which are characterized by the presence of specific chromosomal translocations involving the CBF genes (e.g., t(8;21) or inv(16)). These translocations lead to the formation of fusion genes that result in the production of aberrant transcription factors, which in turn drive the leukemic phenotype. Patients with CBF AML tend to have a higher likelihood of achieving complete remission and longer overall survival compared to other subtypes of AML.

**Why Each Wrong Option is Incorrect**
**Option A:** This option may refer to AML with normal cytogenetics, which has a poorer prognosis compared to CBF AML.
**Option B:** AML with monocytic differentiation (e.g., M4 or M5 subtypes) tends to have a poorer prognosis compared to CBF AML.
**Option C:** AML with t(15;17) (PML-RARA fusion) is characteristic of acute promyelocytic leukemia (APL), which has a relatively good prognosis but is not the best among all AML subtypes.

**Clinical Pearl / High-Yield Fact**
The presence of a CBF abnormality in AML should prompt the clinician to consider a more favorable prognosis, although other factors such as age, performance status, and molecular characteristics also play a crucial role in determining the overall outcome.

**Correct Answer: C.**