**Core Concept**
The question is testing the knowledge of treatment options for Acute Lymphoblastic Leukemia (ALL), a type of cancer that affects the blood and bone marrow. **Chemotherapy** is a crucial component of ALL treatment.

**Why the Correct Answer is Right**
The correct answer includes **Prednisone**, **L-asparginase**, and **Vincristine**, which are commonly used in the treatment of ALL. **L-asparginase** works by depleting the amino acid asparagine, which the leukemia cells cannot synthesize. **Vincristine** is a vinca alkaloid that inhibits microtubule formation, while **Prednisone** is a corticosteroid that induces apoptosis in lymphoid cells.

**Why Each Wrong Option is Incorrect**
**Option A:** Hydroxyurea is used in the treatment of chronic myeloid leukemia and other myeloproliferative disorders, not typically in ALL.
**Option B:** All trans retinoic acid is used in the treatment of acute promyelocytic leukemia (APL), a subtype of acute myeloid leukemia (AML).

**Clinical Pearl / High-Yield Fact**
In the treatment of ALL, a combination of chemotherapeutic agents is often used to achieve remission.

**Correct Answer:** D. L-asparginase