**Core Concept**
Metastasis in neuroblastoma refers to the spread of cancer cells from the primary site in the adrenal gland or along the sympathetic nervous system to distant locations in the body. Neuroblastomas are highly malignant tumors that can exhibit a wide range of clinical behaviors, from spontaneous regression to aggressive progression.

**Why the Correct Answer is Right**
The primary site of metastasis in neuroblastoma is the bone marrow. This is due to the tumor's origin from the sympathetic nervous system, which has a rich innervation of the bone marrow. The cancer cells can infiltrate the bone marrow, leading to widespread dissemination throughout the body. This is in contrast to other cancers, such as breast cancer, which commonly metastasize to the bones but start from epithelial tissues.

**Why Each Wrong Option is Incorrect**
**Option A:**
While the liver is a common site for metastasis in many cancers, it is not the primary site for neuroblastoma metastasis.

**Option B:**
The lungs can be a site for metastasis, but they are not the primary site for neuroblastoma.

**Option C:**
The lymph nodes can be involved in the spread of neuroblastoma, but they are not the primary site for metastasis.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that neuroblastoma can exhibit a wide range of clinical behaviors, and metastasis to the bone marrow is a hallmark of this disease. This can lead to pancytopenia, anemia, and other hematologic abnormalities.

**Correct Answer: D. Bone marrow.**