**Core Concept**
The blood-brain barrier (BBB) is a highly selective permeable barrier that separates the circulating blood from the brain's extracellular fluid. **Lipid solubility** and **molecular weight** are key factors determining a drug's ability to cross the BBB.

**Why the Correct Answer is Right**
Given the correct answer is not specified, let's consider a common anticancer drug that can cross the BBB: **methotrexate**. Methotrexate can cross the BBB, but its ability to do so is limited and can be enhanced by **high-dose therapy**. Other drugs like **vincristine** and **carboplatin** have limited BBB permeability.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option provided, we cannot determine its correctness.
**Option B:** Similarly, without the option, its accuracy cannot be assessed.
**Option C:** This option's correctness is also unknown.
**Option D:** The same applies to this option.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that most anticancer drugs have limited ability to cross the BBB, making **central nervous system (CNS) tumors** challenging to treat.

**Correct Answer:** Not provided in the query.